tJL 


THE  LIBRARY 

OF 

THE  UNIVERSITY 
OF  CALIFORNIA 


PRESENTED  BY 

PROF.  CHARLES  A.  KOFOID  AND 
MRS.  PRUDENCE  W.  KOFOID 


TEXT-BOOK 


OF 


MODERN  CARPENTRY; 


A  TREATISE  ON  BUILDING-TIMBER, 

WITH    RULES    AND    TABLES    FOR    CALCULATING    ITS    STRENGTH,    AND    THE 
STRAINS   TO  WHICH    EACH  TIMBER    OP  A   STRUCTURE 

is  SUBJECTED; 


on  glaofs,  Crosses,  Sribgts,  ttc. 


A     GLOSSARY, 

EXPLAINING    AT    LENGTH    THE    TECHNICAL    TERMS    IN    USE    AMONG 
CARPENTERS. 


BY    THOMAS    W.    SILLOWAT, 


EllustrateH  trg  (Tfomtg  (Copperplates. 

BOSTON: 

CROSBY,   NICHOLS,   AXD    COMPANY, 

117,  WASHINGTON  STREET. 

1858. 


r/iy 


Entered,  according  to  Act  of  Congress,  in  the  year  1858, 

BY    THOMAS    W.    SILLOWAY, 

In  the  Clerk's  Office  of  the  District  Court  of  the  District  of 
Massachusetts. 


BOSTON: 

PRINTED    BY    JOHN   WILSON   AND    SON, 
22.    SCHOOL    STREET. 


PREFACE. 


THE  following  work  has  been  prepared  as  a  book 
of  reference  for  the  master-carpenter,  and  as  a 
manual  of  instruction  for  the  journeyman  and  the 
apprentice.  The  costliness  of  the  works  of  Beli- 
dor,  Rondelet,  Tredgold,  and  others,  places  them 
beyond  the  reach  of  mechanics  of  ordinary  means ; 
and,  being  written  with  reference  to  scientific  for- 
mulas, cannot  be  appreciated,  or  even  understood, 
except  by  those  versed  in  mathematics.  Having 
in  view  the  interests  of  the  large  and  important 
class  above  named,  we  have  scrupulously  avoided 
such  abstruse  algebraic  and  mathematical  formulas 
as  would  more  properly  belong  to  an  encyclopaedia 
of  the  science. 

Works  of  distinguished  authors  have  been  con- 
sulted, but  nothing  selected  which  did  not  commend 
itself  as  of  immediate  practical  utility ;  and,  while 
the  advanced  student  may  perhaps  regret  the 
absence  of  the  higher  mathematics,  it  is  presumed 
that  their  omission  removes  a  great  obstacle  to 
the  progress  of  the  less  learned,  though  not  less 
worthy,  mechanic.  An  extended  essay  on  Car- 


M363539 


iv  PREFACE. 

pentiy  as  a  science  being  rendered  unnecessary 
by  the  comprehensive  nature  of  the  work,  its  place 
is,  we  think,  more  properly  occupied  by  such  prac- 
tical suggestions  as  have  been  considered  most 
useful.  Practice  and  experience,  those  great  and 
successful  teachers  of  all  truth,  are  the  privilege 
of  every  mechanic ;  but  the  lessons  which  they 
convey,  while  perhaps  sufficing  for  his  ordinary 
labors,  may  be  greatly  lightened,  and  far  more 
worthily  directed,  by  a  careful  study  of  those 
results  of  the  experience  and  science  of  others, 
which  it  is  the  aim  of  this  work  to  embody  and 
explain. 

The  portion  of  this  treatise  devoted  to  building- 
timber  states  an  average  of  results  arrived  at 
through  many  experiments  and  much  observation. 
The  authorities  on  the  subject  are  many,  and  the 
field  wide.  It  is,  however,  believed  that  the  few 
pages  allotted  to  the  subject  comprehend  nearly 
all  that  is  of  practical  value  in  the  works  of  Hut- 
ton,  Barlow,  Du  Hamel,  Perronet,  and  many  other 
writers  both  in  Europe  and  America. 

The  illustrations  are  intended  not  only  to  exem- 
plify the  principles  of  the  art,  but  also  to  suggest 
examples  for  imitation  ;  and  the  amount  of  success 
attending  our  efforts  in  selection  —  at  all  times  a 
work  of  much  difficulty  —  must  be  judged  of  by 
the  reader.  He  will,  however,  bear  in  mind  that 
it  has  been  an  important  consideration  to  give  a 
variety  of  each  kind  of  work  in  a  small  compass. 


PREFACE.  V 

The  "  Glossary,"  which  forms  so  large  a  part 
of  the  text,  is  the  result  of  much  labor,  and,  it  is 
hoped,  may  prove  of  corresponding  value. 

Our  work  is  now  presented  to  the  public  in  the 
belief,  that,  notwithstanding  its  imperfections,  it 
contains  a  sufficient  amount  of  information  to  make 
it  a  desirable  companion  to  the  apprentice  in  his 
hours  of  study,  as  well  as  a  ready  assistant  to  the 
man  of  business ;  and,  in  this  hope,  it  is  respect- 
fully dedicated  to  their  service. 

THOS.  W.   SILLOWAY. 

BOSTON,  May,  1858. 


CONTENTS. 


Page. 
CARPENTRY 1 

Nature  and  Properties  of  Timber 6 

Kinds  of  Timber  in  use 12 

Foreign  Timber 21 

Felling  Timber 24 

Seasoning  Timber 30 

Preservation  of  Timber 33 

Durability  of  Timber .38 

Strength  of  Timber 41 

Rules  for  determining  its  Tensile  Strength     ....  45 

„       „            „            „  Cross-strength 52 

»       »            n           »  Compressive  Strength     .    .  59 

GEOMETRY 65 

Square  Hoot 77 

EQUILIBRIUM  OF  STRAINS  ox  TIMBER 81 

SCARFING  TIMBERS 91 

FLOORS 95 

TRUSSED  BEAMS 98 


yiii  CONTENTS* 

Page. 

ROOFS 103 

Observations  on  Eoofs 103 

Timbers  employed  in  Eoofs 107 

Iron-work  employed  in  Roofs 112 

Heavy  Roof-trusses 119 

DOMES .124 

BRIDGES 129 

ARCH-CENTERINGS 134 

JOINTS  IN  FRAMING 139 

IRON  . 141 

Tables  for  calculating  the  Weight  of  Iron-work    .    .  143 
TABLES  FOR  CALCULATING  THE  QUANTITY  OF  TIMBER 

IN  ANY  GIVEN  STICK 147 

GLOSSARY 159 


CARPENTRY. 


THE  Art  of  Carpentry  is  one  of  the  leading 
parts  of  the  sciences  of  architecture  and  en- 
gineering. It  has  claimed  and  received  the  atten- 
tion of  the  masters  in  those  sciences,  and  must 
always  be  a  subject  worthy  of  scientific  considera- 
tion. No  unimportant  portion  of  the  writings  of 
Delorme,  Palladio,  and  even  Vitruvius,  js  that 
which  relates  to  the  art  under  consideration.  The 
frame  of  a  building  sustains  the  same  relation  to 
the  whole  edifice  that  the  bones  of  the  system  do 
to  the  human  body. 

It  is  a  self-evident  truth,  therefore,  that  a  know- 
ledge of  carpentry,  as  a  science,  is  of  great  import- 
ance to  the  builder ;  for  no  edifice  can  be  properly 
constructed  but  in  accordance  with  those  rules  and 
principles  to  which  the  art  is  subject.  Walls  of 
stone  or  brick  may  not  for  their  construction 
demand  this  information ;  still,  to  all  buildings 


2  CARPENTRY. 

there  must  be  roofs,  floors,  and  partitions,  to  con- 
struct which  the  art  of  carpentry  will  be  employed. 

The  first  and  most  important  thing  to  be  con- 
sidered, in  making  or  executing  any  design,  is  the 
end  to  be  attained.  If  a  roof  is  to  be  produced,  it 
is  not  enough  to  know  the  span  and  the  pitch,  but 
it  is  quite  as  essential  to  know  the  material  with 
which  it  is  to  be  covered ;  the  design  best  adapted 
for  the  purpose ;  whether  the  determined  inclina- 
tion is  best  for  that  particular  covering,  &c.  If 
a  floor  is  to  be  built,  the  carpenter  is  to  consider 
the  purpose  for  which  it  \vill  generally,  or  may 
possibly,  be  used ;  if  a  partition  is  to  be  erected, 
what  support  it  may  have  or  may  lack  below,  what 
weight  may  rest  upon  it,  and  to  what  side-strains  it 
may  be  subjected. 

It  is,  however,  unnecessary  to  enumerate,  since 
it  is  plain,  that,  before  commencing  any  work,  it  is 
important  to  see  the  end  as  well  as  the  beginning. 

The  next  consideration  is  so  to  select  both  mate- 
rials and  design  as  to  make  the  best  possible  use  of 
the  means  employed.  This  can  be  done  effectually 
only  by  the  application  of  such  rules  as  investiga- 
tions have  proved  of  value.  A  knowledge  of  the 
nature  and  properties  of  the  kind  of  timber  used, 
its  strength  and  durability,  the  strains  to  which  it 


CARPENTRY.  3 

will  be  subjected,  and  many  other  things  of  like 
nature,  are  of  much  moment  in  the  successful  prac- 
tice of  the  art.  It  was  a  wise  remark  of  Sir  Tho- 
mas Seppings,  that  "the  strength  of  a  piece  of 
framing,  whatever  may  be  the  design,  can  never 
exceed  that  of  its-  weakest  parts;  and  a  partial 
strength  produces  general  weakness." 

The  third  consideration  is  in  regard  to  construc- 
tion itself.  This  science,  like  all  others  in  which 
are  involved  mechanical  principles,  has  many 
parts,  each  of  which  is  closely  interwoven  with  the 
others.  Most  authors  have  divided  the  art  into  two 
parts.  One  is  called  mechanical  carpentry,  and 
treats  of  the  nature  and  properties  of  timber ;  the 
other,  practical  carpentry,  or  the  use  of  timber. 
The  division  is,  to  a  good  degree,  warranted :  yet 
they  are  mutually  dependent ;  and,  in  order  to 
make  a  knowledge  of  one  useful,  it  is  necessary 
to  understand  both. 

Having  determined  the  things  suggested,  and,  in 
addition,  such  incidentals  as  may  be  connected  with 
them,  the  next  step  is  to  execute  the  work.  The- 
ory must  now  give  place  to  practice ;  and  what 
exists  but  on  paper,  or  in  the  imagination  of  the 
artificer,  is  to  be  produced  as  a  thing  of  life.  To 
one  who  has  thoroughly  informed  himself  on  the 


4:  CARPENTRY. 

principles  involved  in  the  work  he  is  to  do,  this 
part  of  his  labor  will  not  be  without  a  correspond- 
ing degree  of  satisfaction  and  entertainment :  for  to 
execute  a  design  is,  or  may  be,  as  inspiring  as  it 
was  to  conceive  and  project  it ;  and  it  is  a  question 
of  some  nicety  to  determine,  whether  the  architect 
and  the  engineer  experience  more  real  pleasure  in 
witnessing  a  design  as  it  is  wrought  out  and  pro- 
duced, than  the  mechanic,  who,  by  care  and  labor, 
gives  to  comparatively  crude  and  unfashioned  ma- 
terials condition  and  form  which  endow  them 
with  a  power  — 

"  That  flings  control 
Over  the  eye,  breast,  brain,  and  soul ; 
Chaining  our  senses  to  the  stone, 

Till  we  become 

As  fixed  and  dumb 
As  the  cold  form  we  look  upon." 

There  are  many  things  essential  for  the  attain- 
ment of  the  desired  end ;  but  the  most  important 
of  them  all,  and,  in  fact,  the  great  and  govern- 
ing principle  involved  throughout,  is,  that  the 
workman  understand  well  every  part  of  his  work, 
and  that  he  be  possessed  of  a  desire  to  excel  in  his 
profession.  In  this,  as  in  all  arts,  "knowledge  is 
power."  The  advice  of  Mr.  Tredgold  is  apt,  and 
to  the  point.  He  says,  "  Nothing  will  assist  the 


CARPENTRY.  O 

artist  more  in  forming  a  good  design  than  just  con- 
ceptions of  the  objects  to  be  attained ;  and  nothing 
will  render  those  objects  more  familiar  to  the  mind 
than  drawing  them." 

To  make  enlarged  copies  of  the  designs  published, 
and  at  the  same  time  to  study  with  care  the  rules 
which  govern  them  and  the  principles  that  are 
involved,  will  insure  success  to  any  one  who  may 
be  disposed  to  make  the  attempt. 


NATURE   AND   PROPERTIES   OF 
TIMBER. 


TIMBER  is  the  substantial  substance  of  all  trees. 
"Woods  differ  in  their  properties  ;  some  being  tough 
and  hard,  while  others  are  brittle  or  soft.  They 
are,  therefore,  of  value  proportional  to  the  kind  of 
work  for  which  they  are  required.  A  great  variety 
of  opinions  exists  in  regard  to  the  manner  in  which 
wood  is  formed.  All  are,  however,  agreed,  that 
the  trunk  and  branches  of  trees  are  composed  of 
three  parts,  —  the  bark,  the  wood,  and  the  pith. 

The  BARK  is  a  covering  which  incases  the  entire 
wood,  and  is  composed  of  three  distinct  parts, — 
the  Epidermis,  the  Cellula,  and  the  Liber. 

The  EPIDERMIS  is  a  thin  skin,  being  the  extreme 
outer  covering. 

The  CELLULA  is  the  organic  matter  next  inside 
the  Epidermis.  It  answers  to  the  flesh  of  animals, 
and  is  formed  into  an  infinite  number  of  tubes. 


PROPERTIES    OF    TIMBER.  7 

The  LIBER  is  the  inner  or  newly  formed  bark. 
The  Epidermis  and  the  Liber  together  form  what 
is  called  the  Cutis,  or  outer  bark,  the  Liber  being 
the  inner. 

The  WOOD  is  the  material  that  exists  between  the 
pith  and  the  bark,  and  is  of  two  kinds,  —  the  heart- 
wood,  or  Duramen  ;  and  the  sap-wood,  or  Alburnum. 

The  HEART-WOOD  is  the  hard  and  dark  part 
next  the  pith. 

The  SAP-WOOD  is  that  which  is  between  the 
heart-wood  and  the  bark. 

The  PITH  is  the  soft  and  spongy  substance  which 
is  enclosed  by  the  heart-wood  at  its  centre. 

In  all  new  shoots,  the  pith  and  bark  are  in  con- 
tact, without  wood  between  them ;  but,  as  the  shoot 
extends,  it  enlarges  by  the  deposit  of  a  secretion 
called  cambium,  which  lies  in  a  cylindrical  ring 
between  the  pith  and  the  bark.  The  deposit  thus 
made  is  of  two  kinds.  One  is  formed  into  bark, 
and  the  other  ultimately  hardens  into  wood.  A 
deposit  of  this  nature  is  made  annually ;  and,  if  the 
trunk  of  a  tree  be  cut  off  across  the  fibres  of 
the  wood,  the  surface  will  present  a  series  of  con- 
secutive layers  or  rings,  so  that  one  is  enabled  to 
determine  by  their  number  the  age  of  the  tree  in 
which  they  exist 


8  PROPERTIES    OF    TIMBER. 

It  is  unusual  to  find  any  two  rings  that  are  alike, 
either  in  regard  to  their  whole  thickness,  or  the 
proportion  of  the  solid  part  to  the  porous ;  the  di- 
mensions and  proportion  being  governed  by  the 
amount  and  nature  of  the  deposit,  some  years  being 
more  favorable  to  each  respectively  than  others. 

So  exact  are  the  laws  by  which  this  is  governed, 
that  the  part  of  the  rings  on  the  north  side  of 
trees  is  thinner,  making  the  heart-wood  nearer 
the  north  side.  This  results  from  the  fact,  that,  the 
south  side  being  more  exposed  to  the  action  of 
the  sun,  the  pores  are  expanded,  and  a  larger 
quantity  of  sap  is  transmitted  through  that  side. 

The  wood  of  no  tree  is  entirely  solid,  but  is  filled 
with  tubes,  or  pores ;  and  the  only  substance  of  a 
solid  nature  that  exists  is  that  which  forms  the 
walls  of  the  cells  before  named.  These  vessels 
are  designed  for  the  conveyance  of  a  fluid  called 
sap,  which  is  absorbed  by  the  roots,  and  passes  up 
through  the  pores  of  the  wood  to  the  leaves,  where 
it  undergoes  a  chemical  change,  and  is  then  re- 
turned through  the  cellula,  or  porous  part  of  the 
bark. 

Sap,  when  it  leaves  the  roots,  is  very  limpid, 
being  nearly  as  thin  as  water :  but,  as  it  passes  up 
through  the  pores,  it  either  meets  with  a  substance 


PROPERTIES    OF    TIMBER.  9 

which  it  dissolves  and  carries  along  with  it,  or,  when 
it  arrives  at  the  most  distant  parts,  is  condensed ; 
for,  on  its  return,  it  is  thickened;  and  entirely 
changed  in  its  nature. 

As  it  passes  downward  through  the  cellula,  it 
gradually  deposits  a  large  proportion  of  the  mate- 
rial it  contains ;  so  that,  when  it  arrives  at  the 
roots,  it  is  as  thin  as  when  it  started  to  pass  up- 
ward. 

As  soon  as  the  leaves  are  developed,  sap  ceases 
to  flow.  The  deposit  gradually  hardens  ;  and 
thus  is  formed  a  new  layer  of  material  for  wood 
and  bark.  From  this  period  till  near  autumn,  ve- 
getation ceases ;  but,  after  this,  the  sap  is  again  in 
motion,  and,  as  it  passes  up,  deposits  along  the 
pores  of  the  wood  the  substance  which  the  ascend- 
ing sap  of  the  next  spring  will  dissolve  and  carry 
along  for  the  formation  of  the  new  wood  and  leaves. 
As  the  tree  increases  in  diameter,  the  wood  at  the 
centre  is  compressed  by  the  growth  of  the  new 
wood  ;  and,  becoming  more  solid,  the  pores  decrease 
in  size,  and  hence  but  little  sap  will  flow  through 
them.  The  part  nearer  the  bark,  being  less  com- 
pressed, is  soft  and  porous  ;  and,  as  the  larger  part 
of  the  sap  passes  through  it,  it  takes  its  name  sap- 
wood. 


10  PROPERTIES    OF    TIMBER. 

Those  parts  of  the  tree  which  need  to  be  elastic 
and  porous  are  continually  receiving  new  substance 
of  a  proper  nature  for  its  replenishment ;  while,  at 
the  same  time,  those  which  are  compressed  into 
hard  wood  serve  to  give  the  requisite  and  additional 
support,  or  back-bone,  to  the  increased  tree.  It  has 
been  well  remarked,  that  the  life  of  a  tree  is  like 
that  of  a  man,  and  may  as  properly  be  divided  into 
three  periods,  —  infancy,  maturity,  and  old  age. 

During  the  whole  of  the  first  period,  the  tree 
continues  to  increase.  Through  the  second,  it 
simply  maintains  itself,  and  neither  loses  nor  gains. 
As  soon,  however,  as  the  heart-wood  begins  to 
decay,  the  second  period  ends,  and  signs  of  old  age 
soon  appear :  and  the  comparison  is  not  then  inapt ; 
for  like  an  old  man  who  seems  to  be  still  fresh 
and  vigorous,  but  whom  one  storm  of  disease  may 
break  and  sweep  away,  so  often  does  a  venerable 
and  revered  oak,  clinging  still  to  life,  as  if  loath  to 
die,  put  on,  with  each  returning  spring,  "  its  youthful 
robes  anew."  But,  its  heart  diseased,  and  vitality 
expended,  being  engaged  in  some  tempestuous  hour 
in  an  unequal  contest,  it  falls  to  rise  no  more. 

The  timber  of  all  trees  partakes,  to  a  greater  or 
less  degree,  of  the  nature  of  the  soil  on  which  it 
grows.  Trees  grown  on  soft  and  spongy  soil  usually 


PROPERTIES    OF   TIMBER.  11 

produce  wood  that  is  comparatively  soft  and  irregu- 
lar in  fibre.  Therefore,  if  oak  be  grown  on  dry 
and  good  land,  the  wood  will  be  solid  arid  tough ; 
but,  if  grown  on  soft  and  wet  land,  it  will  be  pro- 
portionally poor,  and  of  less  value.  This  fact  is 
true  of  all  timber-trees. 

The  wood  of  trees  which  stand  alone,  or  where 
there  are  but  few,  and  those  scattered,  is  better 
than  that  grown  in  the  middle  of  a  forest,  where 
it  is  not  exposed  to  the  sun  and  air.  Hence,  for 
building  purposes,  those  trees  which  stand  alone  are 
to  be  first  selected. 

It  may  be  well  to  mention  here,  that  if  the  soft- 
wood trees  are  very  large  (as  is  often  the  case  with 
some  of  the  pines),  and  most  of  the  branches  are 
near  the  top,  the  wood  near  the  base  of  the  trunk 
is  sometimes  found  to  be  shaky.  This  defect  is 
produced  by  the  action  of  heavy  winds  on  the  top 
of  the  tree,  which  wrenches  or  twists  the  but,  and 
thus  cleaves  apart  the  fibres  of  the  wood. 


12 


BUILDING-TIMBER. 


THERE  are  but  five  kinds  of  wood  in  common  use 
for  carpentry  in  this  country.  These  are  spruce, 
pine,  oak,  hemlock,  and  chestnut. 

SPRUCE  (Abies)  is  indigenous  to  the  colder  parts 
of  North  America,  where  it  grows  in  great  abun- 
dance. For  most  qualities  which  constitute  good 
framing-timber,  it  is  excelled  by  no  other  wood  in 
use. 

There  are  two  varieties,  which  are  familiarly 
known  as  black  or  double  (Pinus  niger)  and  white 
or  single  spruce  (Pinus  alba).  Of  these,  the  black 
is  of  most  value ;  it  being  much  tougher  than  the 
white,  and  may  be  procured  in  much  larger  sticks. 
The  foliage  of  this  variety  is  darker  and  heavier. 
The  white  spruce  is  of  a  comparatively  small 
growth  ;  but  the  wood  may  be  worked  much 
smoother  than  the  other  variety.  Spruce-wood, 
when  seasoned,  is  of  a  clear  yellowish  white,  the 


BUILDING-TIMBER.  13 

annual  rings  being  distinctly  marked  by  a  darker 
tint  of  the  same  color,  and  having  a  silk-like  lustre. 
A  cubic  foot,  when  seasoned,  weighs  thirty-one 
pounds  and  a  half.  It  shrinks,  in  seasoning,  about 
a  seventieth  part  of  its  dimensions,  and  loses  a 
fourth  of  its  weight. 

The  principal  defects  of  this  wood  are  its  liability 
to  twisting  and  splitting  in  the  sun,  and  its  ten- 
dency to  decay  in  all  damp  situations ;  but  where 
due  attention  is  paid  to  these  points,  and  proper 
care  is  exercised  to  prevent  the  exposures  named, 
little  else  need  be  done  to  insure  the  permanency 
of  work  composed  of  this  wood. 

PINE  (Pinus)  is  next  in  value  as  material  for  a 
frame.  Of  this  wood,  there  are  many  species. 
The  family  (  Conifera)  to  which  it  belongs  is  large, 
and  comprises  all  that  ranges  from  the  most  com- 
pact and  hard  spruce  to  the  softest  white  pine. 
But  two  kinds,  however,  will  claim  our  attention ; 
the  others,  as  framing-timber,  partaking  largely 
of  the  nature  of  spruce.  Remarks  relating  to  that 
wood  may  be  applied  with  nearly  the  same  pro- 
priety to  all  the  harder  varieties  of  pine. 

The  two  varieties  most  in  use  are  known  as 
white  pine  and  Carolina  pine. 

WHITE  PINE  (Pinus  strobus)  abounds  in  all  the 


14  BUILDING-TIMBER. 

northern  portion  of  the  United  States,  and  is 
the  tallest  of  our  native  trees.  It  is  remarkable 
for  the  straightness  of  its  trunk,  which  is  often 
found  a  hundred  feet  high,  entirely  clear  of  limbs. 
The  whole  tree  frequently  attains  an  altitude  of 
two  hundred  feet.  It  is  the  same  as  that  known  in 
England  as  Weymouth  pine.  In  forests,  all  except- 
ing the  top  branches  decay  early ;  and  these,  being 
above  all  other  trees,  make  it  conspicuous  as  far  as 
it  can  be  seen.  Pine  is  of  rapid  growth,  and,  in 
favorable  situations,  increases  an  inch  in  diameter, 
and  two  feet  in  height,  in  a  single  year.  The  bark  of 
trees  which  are  less  in  diameter  than  fifteen  inches  is 
very  smooth,  and  of  a  bottle-green ;  being,  through 
the  warm  season,  covered  with  an  ashy  gloss. 

The  color  of  the  seasoned  wood  is  a  brownish 
white.  A  cubic  foot  weighs  twenty-four  pounds 
and  three-quarters.  Its  decrease  of  dimension  in 
seasoning  is  slightly  more  than  spruce.*  It  has 
little  tendency  to  warp  or  twist ;  and,  for  such  parts 
of  a  frame  as  are  liable  to  be  exposed  to  dampness 
and  continued  wet,  it  is  preferable  to  spruce.  The 
wood  being  softer,  it  is  more  liable  to  indentation 


*  It  is  the  generally  received  opinion  of  carpenters,  that  all 
wood  is  liable  to  some  shrinkage  in  length;  though,  in  most 
instances,  it  is  hardly  perceptible. 


BUILDING-TIMBER.  15 

at  the  joints ;  and,  being  less  stiff,  it  is  not,  for 
general  purposes,  entirely  equal  to  spruce.  As  a 
whole,  its  average  value  for  framing  purposes  may 
be  considered  as  nine  to  ten. 

For  finishiny-lumler,  it  excels  all  others,  and 
sustains  the  same  relation  to  joinery  that  spruce 
does  to  carpentry.  None  is  better  calculated  to 
withstand  the  effects  of  the  sun  and  weather  than 
this ;  for  with  the  exercise  of  proper  care  in  sea- 
soning, and  reasonable  protection  afterwards,  it  will 
retain  its  natural  strength  and  vigor  as  long  as  the 
best  of  oak. 

CAROLINA  PINE  (Pinus  australis)  is,  in  most 
respects,  entirely  unlike  the  wood  last  described; 
being  very  compact,  and  thoroughly  saturated  with 
a  resin,  or  pitch,  which  is  remarkable  for  its  intense 
fragrance.  It  grows  in  great  luxuriance  in  all  our 
States  south  of  Virginia,  and  is  familiarly  known 
at  the  north  as  southern  pine.  Timber  of  almost 
any  reasonable  length  and  dimensions  may  be  easily 
obtained.  This  wood  is  seldom  cut  up  into  small 
joists ;  but,  when  not  sawed  into  large  framing- 
timber,  it  is  used  for  planks  and  floor-boards ; 
the  solidity  of  the  wood,  and  the  fineness  of  its 
grain,  making  it  of  great  value  for  the  purpose 
last  named. 


16  BUILDING-TIMBER. 

In  all  dry  situations,  it  is  exceedingly  durable ; 
but,  in  wet  or  even  damp  places,  it  loses  its  vigor, 
and  soon  moulds  and  decays.  Its  tensive  strength, 
compared  with  oak,  is  nearly  equal ;  while  its  weight 
is  much  less.  This  quality,  added  to  its  peculiar 
stiffness  and  resilience,  has  of  late  years  made 
it  a  rival  of  oak,  where  a  lighter  yet  solid  wood  is 
required.  It  is,  however,  very  brittle,  and  liable 
to  fracture  by  a  sudden  blow  or  concussion  ;  making 
it  inferior  to  oak,  where  toughness  is  needed. 

This  wood,  when  newly  planed,  is  a  rich  yellow ; 
the  resinous  parts  giving  it  a  finely  variegated  ap- 
pearance. The  average  weight  of  a  cubic  foot, 
when  seasoned,  is  not  far  from  thirty-eight  pounds 
and  a  quarter.  It  decreases  a  fifth  of  its  weight 
in  seasoning,  and  a  sixty-fifth  of  its  dimensions ; 
shrinking  something  more  in  the  direction  of  its 
length  than  either  of  the  other  woods  in  common 
use. 

OAK  ( Quercus)  is  a  wood,  like  all  others,  exist- 
ing in  many  species.  Only  two,  however,  —  those 
commonly  known  as  white  oak  and  yellow  oak,  — 
are  in  general  use  for  building  purposes.  It  is  a 
native  of  temperate  climates,  and  is  found  in  great 
perfection  and  vigor  in  the  United  States,  —  from 
Virginia  (the  northern  limit  of  the  growth  of  Ca- 


BUILDING-TIMBER.  17 

rolina  pine)  to  the  Canada  line.  The  wood  is  very 
durable,  when  kept  immersed  in  water ;  and,  while 
remaining  in  a  perfectly  dry  situation,  it  has  lasted 
more  than  a  thousand  years.  When  subjected 
alternately  to  the  action  of  water  and  air,  together 
with  more  than  ordinary  warmth,  it  is  subject  to 
early  decay.  Oak-wood  is  hard,  yet  elastic  and 
tough.  Its  texture  is  alternately  porous  and  solid ; 
the  porous  sections  being  the  lighter  colored  por- 
tion of  the  annual  ring.  The  wood  of  young 
trees  is  much  tougher  than  that  of  old  ones,  and 
is  more  difficult  to  work.  That  of  old  ones  is 
often  quite  brittle ;  while  at  the  same  time,  in 
most  other  respects,  it  appears  to  retain  its  natural 
qualities.  It  is  the  case  with  oak  as  with  all 
trees,  —  that  the  wood,  taken  from  the  body  and 
large  limbs,  is  stronger  than  that  taken  from 
the  small  branches.  The  sap  is  possessed  of  a 
peculiar  odor  and  taste.  It  contains  gallic  acid; 
and,  in  consequence,  turns  black  or  purple,  when 
brought  in  contact  with  iron. 

The  color  of  the  wood  is  a  whitish  brown  in  the 
white  species,  and  a  yellowish  brown  in  the  yellow. 
A  cubic  foot,  when  dry,  weighs  forty-eight  pounds. 
It  shrinks,  in  seasoning,  a  thirty-sixth  part  of  its 
dimensions,  and  loses  a  third  of  its  weight. 
2 


18  BUILDING-TIMBER. 

For  many  purposes,  —  such  as  strengthening- 
pieces,  keys,  treenails,  &c.,  —  oak  is  indispensable  ; 
though  of  late  years,  as  a  general  framing-timber, 
it  has  been  little  used.  For  the  first  two  centu- 
ries after  the  settlement  of  this  country,  it  was 
employed  almost  to  the  entire  exclusion  of  other 
wood ;  but  spruce  and  pine  have  gradually  sup- 
planted it,  till  now  a  new  piece  of  oak-framing  is 
but  seldom  seen.  When  used  to  any  great  extent, 
it  is  for  open  timber-roofs  of  churches,  or  some- 
thing of  the  kind.  The  natural  beauty  of  its  se- 
lected wood  for  a  rich  finish-lumber,  and  its  great 
strength  and  durability  as  a  framing-timber,  insure 
the  usefulness  and  value  of  the  "  monarch  of  the 
forest." 

In  addition  to  the  foregoing,  the  two  next  in 
value  are  those  familiarly  known  as  the  black  oak 
and  the  live  oak.  The  former  is  nearly  allied  to 
the  yellow  oak ;  and  is,  in  many  respects,  of  equal 
value.  Live  oak  is  principally  used  in  ship- 
building. The  wood  is  nearly  identical  with  white 
oak;  but  the  nature  and  habits  of  the  tree  tend 
to  produce  only  small  and  very  crooked  timber. 
For  the  various  purposes,  however,  for  which  the 
timber  is  used,  it  is  an  important  member  of 
the  Quercus  family. 


BUILDING-TIMBER.  19 

HEMLOCK  (Canadensis)  is  often  used  in  the 
cheaper  kinds  of  carpentry.  It  is  indigenous  to 
nearly  all  places  which  are  favorable  to  the  produc- 
tion of  spruce  and  the  light  pines.  In  dry  situations, 
when  the  wood  has  been  properly  seasoned,  and  is 
carefully  protected  from  the  action  of  the  sun,  it 
may  be  considered  as  a  fourth-rate  wood.  Its  pe- 
culiar structure,  tending  to  twistish  or  cleftish  grain, 
makes  it  entirely  unreliable  for  large  timbers  where 
either  tensile  or  compressive  strain  is  required. 
It  decays  quickly  in  damp  situations ;  and,  if 
exposed  while  in  an  unseasoned  state,  its  heart- 
wood  cleaves  from  the  surrounding  wood  by  the 
action  of  either  sun  or  wind. 

Considering  these  tendencies  (existing  even  in 
the  best  specimens),  it  is  usually  cut  into  small 
studding-joists  or  common  boards.  Hemlock  pos- 
sesses one  quality  in  common  with  oak  and  the 
other  hard  woods ;  viz.,  the  tenacity  with  which  it 
adheres  to  a  nail.  An  ordinary  tenpenny  cut  nail, 
if  driven  into  the  wood  half  its  length,  will  part 
before  it  can  be  drawn  out.  This  quality  is  one 
of  its  first  recommendations  for  common  or  rough 
boarding,  as  it  firmly  holds  the  nails  of  shingling, 
slating,  clapboarding,  &c. 

The  sap  is  possessed  of  an  intense  and  some- 


20  BUILDING-TIMBER. 

what  unpleasant  odor.  It  is  unfit  for  use  while 
in  an  unseasoned  state,  as  it  corrodes  iron  im- 
mediately at  the  part  where  it  begins  to  project 
from  the  wood.  The  color  of  the  wood  is  a  light 
brown ;  and  a  cubic  foot,  when  dry,  weighs  twenty- 
seven  pounds.  It  shrinks,  in  seasoning,  a  little 
less  than  spruce,  and  loses  one-fourth  of  its 
weight. 

CHESTNUT  ( Castanet)  is  a  wood  of  great  value, 
and  is  in  most  respects  nearly  identical  with  oak, 
which  it  resembles  in  color,  toughness,  and  solidity. 
It  is  a  native  of  temperate  regions,  and  is  usually 
found  growing  side  by  side  with  its  rival.  For 
most  purposes  for  which  oak  is  used,  chestnut  is 
of  equal  value.  While  exceedingly  durable  in 
damp  situations,  it  is  equally  so  in  those  which  are 
dry ;  and,  in  places  partaking  at  times  of  both,  it 
.is  preferable  to  oak.  For  posts  set  in  the  ground, 
it  may  be  considered  good  for  a  service  of  forty 
years.  Like  oak,  the  grain  of  the  wood  is  com- 
pact ;  and  that  of  young  trees  is  very  tough  and 
flexible:  but  old  wood  is  liable  to  brittleness,  ap- 
pearing sound  and  healthy  without,  while  within 
it  is  decayed  and  rotten.  Chestnut  contains  one 
valuable  quality  not  possessed  by  either  of  the 
other  woods ;  namely,  when  once  seasoned,  it  is 


BUILDING-TIMBER.  21 

but  slightly  susceptible  of  shrinking  or  swelling. 
The  weight  of  a  cubic  foot  of  the  wood,  when  per- 
fectly seasoned,  is  forty-one  pounds. 


FOREIGN  TIMBER. 

As  many  scientific  experiments  have  been  made 
in  Europe  on  woods  which  are,  in  their  general 
properties  and  strength,  nearly  identical  with  those 
in  common  use  in  America,  a  brief  synopsis  of 
these  will  be  given,  that  the  carpenter  may  avail 
himself  of  the  experiments  by  applying  the  results 
to  our  corresponding  timber. 

ACACIA  (Robina), —  a  wood  commonly  known 
in  America  as  locust.  A  cubic  foot,  when  seasoned, 
weighs  forty-eight  pounds.  It  is  slightly  stronger 
than  oak. 

CHRISTIANA  DEAL  (Pmus  abies),  —  a  wood 
nearly  allied  to  the  spruce  of  North  America. 
It  is  somewhat  heavier  and  tougher.  It  will 
bear  one-fifth  more  strain,  and  is  also  one-fifth 
stiffer. 

COWRIE  (Dammara  australis),  —  a  New-Zea- 
land tree,  the  wood  of  which  answers  well  to  the 


22  BUILDING-TIMBER. 

pitch  or  yellow  pine  growing  in  the  New-England 
States.  A  cubic  foot,  when  seasoned,  weighs 
forty  pounds.  Its  general  strength  is  that  of  our 
spruce. 

DANTZIC  OAK  is  of  the  same  stiffness  as  our 
white  oak,  but  is  tougher  and  stronger. 

ENGLISH  OAK  (Quercus  robur)  is  one-tenth 
lighter,  and  one-seventh  stronger,  than  our  white 
oak;  and,  while  it  is  one-fourth  tougher,  it  is  not 
as  stiff  by  one-SBventh. 

MAR-FOREST  FIR  (Pinus  sylvestris),  —  a  wood 
which,  in  New  England,  would  be  considered  as  a 
cross  between  spruce  and  northern  pitch-pine.  A 
cubic  foot,  when  dry,  weighs  thirty-eight  pounds. 
It  is  of  the  same  tensile  strength  as  our  spruce, 
but  less  elastic. 

MEMEL  FIR,  —  a  wood  nearly  identical  with 
that  from  Mar  Forest.  It  answers  well  to  the  red 
and  yellow  pines  of  New  England,  but  partakes 
of  the  nature  of  spruce,  in  being  stiffer  than  the 
pines  named. 

NORWAY  SPRUCE  (Pinus  abies)  is,  in  many 
respects,  like  our  black  spruce.  It  is  harder,  and 
has  more  pitch.  "When  seasoned,  it  weighs  thirty- 
four  pounds  to  a  cubic  foot. 

RIGA   OAK   is   one-seventh   stronger   than    our 


BUILDING-TIMBER.  23 

white  oak,  but  is  one-seventh  less  stiff.  It  is  one 
of  the  toughest  varieties  of  oak  in  use. 

SCOTCH  FIR  is  nearly  identical  with  our  New- 
England  red  and  yellow  pine. 

WEYMOUTH  PINE  (Pinus  strobus)  is  a  wood 
identical  with  the  white  pine  of  New  England. 


FELLING  TIMBER. 


THE  felling  of  timber  was  looked  upon  by  ancient 
architects  as  a  matter  of  much  moment.  Vitru- 
vius  was  so  minute  in  giving  advice  on  this  subject, 
as  to  urge  that  timber  should  never  be  felled  but 
in  the  decrease  of  the  moon;  and  we  find  good 
Isaac  Ware  saying  of  the  suggestion  (it  being  what 
he  termed  the  opinion  of  the  "  Roman  oracle  "), 
"  This  has  been  laughed  at,  and  supposed  to  be  an 
imaginary  advantage.  .  .  .  There  may  be  good  in 
following  the  practice ;  there  can  be  no  harm :  and 
therefore,  when  I  am  to  depend  upon  my  timber,  I 
will  observe  it."  Sir  John  Evelyn  quaintly  says, 
"  It  should  be  in  the  vigor  and  perfection  of  trees 
that  a  felling  should  be  celebrated." 

'The  end  to  be  attained  in  the  management  of 
timber-trees  is  to  produce,  from  a  given  number, 
the  largest  possible  amount  of  sound  and  durable 
wood. 


FELLING    TIMBER.  25 

To  accomplish  this  requires  not  only  attention 
in  felling  the  timber,  but  in  caring  for  it  after- 
wards. The  first,  and  perhaps  most  important, 
advice  is  to  fell  a  tree  as  near  the  time  of  its 
maturity  as  possible :  for,  if  it  be  cut  earlier,  the 
sap-wood  predominates ;  and,  the  heart-wood  being 
comparatively  soft,  the  timber  cannot  possess  great 
strength  or  much  durability.  If  permitted  to 
stand  long  after  this,  it  declines  in  quality;  the 
wood  by  degrees  losing  its  elasticity,  and  becoming 
brittle. 

It  is  somewhat  difficult  to  decide  just  when  a 
tree  is  at  maturity.  From  the  investigations  of 
naturalists,  however,  it  may  be  safe  to  consider, 
that  hard-wood  trees,  as  oak  and  chestnut,  should 
never  be  cut  before  they  are  sixty  years  old ; 
the  average  age  for  felling  being  a  hundred  years. 
For  the  soft  woods,  —  as  spruce  and  pine,  —  the 
proper  age  is  seventy  years.  It  should  be  remem- 
bered, that  the  times  mentioned  are  by  no  means 
arbitrary ;  for  situation,  soil,  &c.,  have  much  to  do 
with  it. 

When  a  tree,  under  conditions  favorable  to  its 
growth,  entirely  ceases  increasing  the  diameter  of 
its  trunk,  and  loses  its  foliage  earlier  in  the  autumn 
than  it  is  wont  to  do,  these  facts  may  be  considered 


26  FELLING    TIMBER. 

as  indications  of  decline,  and  that  the  tree  is  of 
sufficient  age  to  be  felled. 

The  next  consideration  is  the  season  of  the 
year  most  favorable  for  the  work.  All  investi- 
gations tend  to  prove  that  the  only  proper  time 
is  that  at  which  the  tree  contains  the  least  sap. 
As  stated  in  another  article,  there  are  two  seasons 
in  each  year  when  the  vessels  are  filled.  One  is  in 
the  spring,  when  the  fluid  is  in  motion  to  supply 
nutriment  to  the  leaves,  and  deposit  material  for 
new  wood :  the  other  is  in  the  early  part  of  the 
autumn,  when,  after  the  stagnation  which  gives 
the  new  wood  time  to  dry  and  harden,  it  again 
flows  to  make  the  vegetable  deposits  in  the  vessels 
of  the  wood.  At  neither  of  these  times  should 
trees  be  felled ;  for,  if  the  pores  be  full  of  vege- 
table juices,  —  which,  being  acted  upon  by  heat  and 
moisture,  may  ferment,  —  the  wood  will  decay. 

In  the  New-England  States,  August  is,  for  this 
purpose,  the  best  month  in  the  year ;  for,  at  that 
time,  most  of  the  fluids  and  vegetable  matter 
having  been  exhausted  in  the  formation  of  leaves 
and  wood,  and  the  watery  parts  evaporated,  the 
wood  is  dryest.  Next  to  this  is  the  month  of 
January ;  for  then,  as  in  August,  there  is  but  little 
sap  in  the  tree. 


FELLING    TIMBER.  27 

The  age  at  which  trees  should  be  felled,  and  the 
most  suitable  time  for  the  work,  having  been  deter- 
mined, there  are  two  other  things  which  claim  at- 
tention. 

The  first  of  these  is  the  removal  of  the  bark 
from  the  trunk  and  principal  branches  of  the  trees. 
This  practice  has,  from  time  immemorial,  been 
considered  of  inestimable  value :  for,  bj  it,  the 
sap-wood  is  rendered  as  strong  and  durable  as 
the  heart-wood ;  and,  in  some  particular  instances, 
experiments  have  shown  it  to  be  four  times  as 
strong  as  other  wood,  in  all  respects  similar,  and 
grown  on  the  same  soil,  but  felled  with  the  bark 
on,  and  dried  in  sheds.*  Buffon,  Du  Hamel,  and, 
in  fact,  most  naturalists,  have  earnestly  recom- 
mended the  practice.  The  venerable  Evelyn,  in 
his  "  Sylvia,"  says,  "  To  make  excellent  boards  and 
planks,  it  is  the  advice  of  some,  that  you  should 
bark  your  trees  in  a  fit  season,  and  so  let  them 
stand  naked  a  full  year  before  felling." 

In  regard  to  the  time  that  should  elapse  between 
the  removal  of  the  bark  and  the  felling  of  a 
tree,  a  variety  of  opinions  exists.  It  was  the  usual 
custom  of  early  architects  to  remove  the  bark  in 
the  spring,  and  fell  the  trees  the  succeeding  winter. 
*  Emerson's  "  Trees  and  Shrubs  of  Massachusetts,"  p.  33. 


28  FELLING    TIMBER. 

Later  investigations  have  proved  that  it  is  better 
to  perform  this  work  three,  or  even  four,  years 
in  advance,  instead  of  one.  Trees  will,  in  most 
situations,  continue  to  expand  and  leaf  out  for 
several  seasons  after  the  bark  has  been  removed. 
The  sap  remaining  in  the  wood  gradually  becomes 
hardened  into  woody  substance ;  thereby  closing  the 
sap-vessels,  and  making  it  more  solid.  As  bark 
separates  freely  from  the  wood  in  spring,  while 
the  sap  is  in  motion,  it  should  be  taken  off  at 
that  period. 

The  second  suggestion  is  to  cut  into  and  around 
the  entire  trunk  of  the  tree,  near  the  roots,  so 
that  the  sap  may  be  discharged ;  for,  in  this  manner, 
it  will  be  done  more  easily  than  it  can  be  by 
evaporation  after  the  tree  is  felled.  In  addition 
to  this,  if  it  be  permitted  to  run  out  at  the  incision, 
a  large  portion  of  the  new  and  fermentable  matter 
will  pass  out  with  it,  which  would  remain  in  the  wood 
if  only  such  material  is  removed  as  would  pass  off 
by  evaporation. 

This  cutting  should  be  made  in  the  winter  pre- 
vious to  the  August  in  which  the  tree  is  to  be 
felled ;  and  the  incision  should  be  made  as  deep  into 
the  heart-wood  as  possible,  without  inducing  a 
premature  fall  of  the  tree. 


FELLING    TIMBER.  29 

Many  suggestions  might  be  made  as  regards 
the  mechanical  operation  in  felling  trees :  but,  as 
these  are  familiar  to  all  intelligent  workmen,  we 
will  mention  only  one;  namely,  the  value  of  re- 
moving from  the  side  of  the  tree  such  branches 
as  will  strike  the  ground  when  it  falls,  and,  by 
wrenching,  cleave  the  grain  of  the  wood,  and 
thereby  injure  the  timber.  Such  defects,  which 
are  often  found  after  the  timber  has  become  sea- 
soned, could  not  be  discovered  when  it  left  the 
mill. 


30 


SEASONING  TIMBER. 


NOTHING  contributes  more  to  increase  the  value 
of  timber  than  thorough  and  judicious  seasoning. 
The  principal  objects  to  be  attained  are,  first,  to 
remove  the  saccharine  or  loose  vegetable  matter, 
which  by  heat  and  moisture  may  ferment,  and 
thereby  cause  the  wood  to  decay ;  and,  second,  to 
remove  all  moisture,  in  order  that  the  wood  may 
shrink  to  its  smallest  dimensions,  and  thus  be  en- 
abled to  retain  its  shape  and  place  after  it  has  been 
wrought.  To  attain  this,  many  methods  have  been 
used ;  but,  fortunately,  the  most  simple  and  practical 
of  them  all  is  of  most  value.  If  timber  be  properly 
subjected  to  the  action  of  water  and  air,  it  may, 
by  this  means,  be  perfectly  seasoned,  and  at  small 
expense. 

As  soon  as  it  has  been  felled,  timber  should  be 
immediately  removed  to  the  mill,  and  sawed.  If 
this  is  impracticable,  and  the  bark  has  not  been 


SEASONING    TI3IBER.  31 

removed,  it  should  be  taken  off,  and  the  logs  put 
into  the  river  or  some  running  stream,  there  to 
remain  till  they  can  be  taken  to  the  mill. 

If  no  stream  is  near,  they  should  be  placed  on 
some  dry  spot,  be  well  blocked  up  from  the  ground, 
and  covered  with  boughs  of  trees  to  keep  from 
them  the  action  of  the  hot  sun  or  of  strong  cur- 
rents of  wind. 

After  the  lumber  has  been  sawed,  it  should  be 
put  into  the  water,  and  chained  down  beneath  its 
surface,  for  at  least  two  weeks,  when  the  vegetable 
matter  will  be  dissolved,  and  pass  out  into  the 
water.  After  remaining  submerged  for  the  time 
named,  it  should  be  taken  out,  and  piled  in  a  dry 
place,  where  it  may  be  covered  with  boards  to 
protect  it  from  the  direct  action  of  both  sun  and 
wind. 

It  is  not  well  to  attempt  to  dry  it  too  quickly ; 
for,  if  it  be  subjected  to  great  heat,  a  large  portion 
of  the  carbon  will  pass  off,  and  thereby  weaken  the 
timber.  And,  further,  if  it  be  dried  by  heat, 
the  outside  will  become  hardened,  and  the  pores 
closed ;  so  that  moisture,  instead  of  passing  out, 
will  be  retained  within.  Timber,  too  suddenly 
dried,  cracks  badly,  and  is  thus  materially  in- 
jured. 


32  SEASONING    TIMBER. 

In  piling  it,  the  sleepers  on  which  the  first  pieces 
are  laid  should  be  perfectly  level  and  "out  of 
wind,"  and  so  firm  and  solid  throughout,  that  they 
will  remain  in  their  original  position ;  for  timber, 
if  bent  or  made  to  wind  before  it  is  seasoned,  will 
generally  retain  the  "same  form  when  dried.  Pieces 
of  wood  should  be  put  between  the  sticks,  and  each 
piece  directly  over  the  other,  so  that  air  may  freely 
pass  through  the  whole  pile ;  for,  while  it  is  neces- 
sary to  shield  timber  from  strong  draughts  of  wind 
and  the  direct  action  of  the  hot  sun,  a  free  cir- 
culation of  air  and  moderate  warmth  are  equally 
essential. 

More  costly  methods  of  seasoning  —  such  as 
smoking,  steaming,  exhausting  the  sap  by  an  air- 
pump,  &c.  —  are  not  sufficiently  valuable  to  com- 
pensate for  the  trouble  and  expense. 

The  length  of  time  requisite  for  seasoning  tim- 
ber depends  entirely  upon  the  size  of  the  stick,  the 
kind  of  wood,  its  situation,  &c.,  while  drying.  The 
carpenter  should  exercise  his  own  judgment  ; 
always  remembering  that  a  large  stick  is  never  so 
dry  that  it  will  not  season,  and  consequently  shrink 
still  more,  if  sawed  into  smaller  pieces,  and  new 
surfaces  be  exposed  to  the  action  of  the  air. 


33 


THE   PRESERVATION   OF    TIMBER. 


To  preserve  timber  is  next  in  importance  to  ob- 
taining it ;  for,  unless  properly  cared  for,  however 
good  may  be  the  material,  all  previous  precautions 
avail  but  little.  Wood  is  liable  at  any  time  to 
change  its  nature,  and  part  with  its  most  valuable 
properties.  In  all  timber,  even  if  well  seasoned, 
there  remains  a  certain  quantity  of  sap  and  vege- 
table matter,  which,  when  the  piece  is  shut  up  in 
stagnant  air  liable  to  be  heated  in  summer,  will 
mould  or  ferment,  and  an  acid  be  formed,  decom- 
posing the  wood. 

In  no  instance  should  a  piece  of  framing  be  so 
enclosed  that  fresh  air  cannot  at  all  times  come  in 
contact  with  it.  To  every  roof,  church-spire,  dome, 
&c.,  there  should  be  air-holes  at  such  points  above 
and  below  as  will  insure  a  continual  circulation  of 
air  about  the  wood. 

The  next  consideration  is  to  protect  it  from  the 


34  THE    PRESERVATION    OF    TIMBER. 

action  of  alternate  moisture  and  dryness.  If  a 
stick  of  timber  be  exposed  to  a  continued  heat,  — 
as,  for  instance,  over  a  baker's  oven,  —  it  will  in 
time  lose  its  elastic  power,  and  become  brittle. 
If,  on  the  other  hand,  a  piece  of  the  same  timber, 
in  all  respects  identical  in  properties  and  nature, 
be  immersed  in  water,  and  remain  submerged,  it 
will  retain  the  larger  part  of  its  properties  for 
centuries.  In  fact,  if  not  injured  by  insects  or 
acids  in  the  water,  it  may  be  considered  as  almost 
indestructible  ;  but  the  reverse  of  this  is  the  case 
if  it  be  subjected  to  the  alternate  action  of  water 
and  air. 

As  soon  as  a  piece  of  wood  is  exposed  to  the 
action  of  moisture,  the  vegetable  and  saccharine 
matter  begins  to  dissolve;  and  a  slimy  coating  is 
formed  wherever  the  solution  exists.  When  ex- 
posed to  the  air,  this  slime  ferments ;  and  from  it 
grows  a  sort  of  fungus,  which  lives  on  the  vital 
parts  of  the  wood  itself.  A  continual  series  of 
exposures  of  this  kind  soon  induces  a  visible  de- 
cay, which  ends  in  the  entire  destruction  of  the 
timber. 

Every  part  of  a  frame  should  in  some  way  be 
protected.  No  work  should,  therefore,  be  placed 
on  or  very  near  the  ground,  where  earth  can  in 


THE    PRESERVATION    OF    TIMBER.  35 

any  way  come  into  immediate  contact  with  it ; 
nor  should  any  be  subjected  to  the  direct  action 
of  steam  or  vapor,  without  being  in  some  way 
shielded.  The  artificial  methods  of  preserving 
timber  are  numerous.  Covering  the  work  with 
boards  is  in  many  instances  effectual.  Sometimes, 
however,  this  is  no  protection,  but,  on  the  con- 
trary, serves  to  retain  moisture  that  would  evapo- 
porate  if  left  exposed,  as  is  often  the  case  with  the 
sills  of  buildings,  timber-bridges,  &c. 

In  every  instance  where  the  timber  must  be 
covered,  but  is  necessarily  exposed  to  moisture, 
also  when  it  is  exposed  to  the  action  of  the  weather 
without  a  covering,  artificial  means  for  preservation 
must  be  resorted  to. 

The  first  step  to  be  taken  is  to  season  the  tim- 
ber thoroughly.  When  this  has  been  done,  the 
whole  of  the  exposed  surfaces  should  be  covered 
with  some  preparation  that  will  strike  into  the 
wood,  and,  as  much  as  possible,  harden  the  outside. 
Thus,  by  closing  the  pores,  the  piece  is  made  im- 
pervious to  the  weather. 

A  valuable  practice  for  the  preservation  of  tim- 
ber is  to  heat  it  by  burning  charcoal,  or  something 
of  like  nature,  beneath ;  and,  while  it  is  in  a  heated 
state,  applying  a  hot  solution  of  an  ounce  and  a 


36  THE    PRESERVATION    OF    TIMBER. 

half  of  corrosive  sublimate,  or  one  of  aqua  fords 
(nitric  acid),  in  a  gallon  of  water.  After  this  is 
done,  and  the  work  well  dried,  it  should  be  painted 
with  the  best  quality  of  white  lead  and  oil. 

A  thin  solution  of  hot  coal-tar  and  whale-oil  is 
of  great  benefit  to  all  timber  that  is  to  be  placed 
near  the  ground.  If  this  operation  be  repeated 
two  or  three  times,  and  finely  pulverized  clinkers 
from  a  blacksmith's  forge,  or  the  dust  made  from 
the  scales  of  iron  which  lie  about  an  anvil,  be  sifted 
upon  the  timber  while  the  tar  is  newly  put  on,  it 
will  possess  great  durability,  since  wood  prepared 
in  this  manner  is  scarcely  susceptible  of  decay. 

Pyroligneous  acid,  or  the  liquor  that  drips  from 
stove-pipes  in  which  vapor  condenses,  also  strong 
decoctions  of  soot  applied  hot,  are  recommended  as 
good  preservative  agents.  In  all  framing  exposed 
to  the  weather,  every  mortise  that  can  hold  water, 
and  their  tenons,  together  with  all  the  wood  about 
them,  should  have  a  good  coating  of  one  of  the 
preparations  first  named,  before  the  work  is  put 
together. 

It  not  unfrequently  occurs  that  the  wood  at  the 
lower  end  of  posts,  rafters,  &c.,  of  church-steeples, 
is  found  to  be  entirely  decayed,  while  other  parts 
of  the  structure  are  perfectly  sound.  In  almost 


THE  PRESERVATION  OF  TIMBER.       37 

all  such  cases,  some  part  of  the  work,  being  imper- 
fect, has  admitted  water,  which,  following  down  the 
post  to  its  end,  has  -filled  the  mortise,  and  thus 
rotted  the  wood. 

When  a  piece  of  framing  is  to  be  permanently 
exposed  to  the  weather,  it  should  be  treated  with 
one  of  the  solutions  first  described,  and  then  tho- 
roughly painted  and  sanded.  Wood  in  a  proper 
condition  when  felled,  afterwards  thoroughly  sea- 
soned, well  saturated  with  diluted  corrosive  subli- 
mate, and,  finally,  kept  properly  painted  and  sanded, 
is  as  durable  as  it  ever  can  be. 

One  caution  it  would  be  well  to  remember ; 
namely,  to  refrain  from  applying  paint  or  any 
preparation  to  wood  before  it  is  thoroughly  sea- 
soned :  for,  should  the  outside  be  coated  so  as 
effectually  to  prevent  impenetration  from  without, 
evaporation  will  also  be  prevented  from  within  ; 
therefore,  all  moisture  that  may  be  in  the  wood  will 
be  retained,  and  rot  the  piece. 

Another  suggestion  is  to  use  timbers  as  small 
as  the  nature  of  the  work  will  permit.  It  is*  a 
mistake  to  suppose  that  large  timbers  will  continue 
good  longer  than  small  ones.  We  may  see  an 
exemplification  of  this  at  any  New-England  farm- 
house. The  light  spokes  of  a  wheel  will  remain 


38  THE    PRESERVATION    OF    TIMBER. 

sound  and  strong  for  years  after  the  tongue  of  the 
cart  to  which  they  belonged  has  entirely  decayed. 

If  a  timber  is  sufficiently  Strong  when  first  used 
(the  requisite  allowance  being  made  for  permanent 
strain),  all  has  been  done  that  prudence  would 
dictate,  since  no  increase  of  the  dimensions  of 
the  piece  will  insure  its  longer  duration.  And, 
finally,  it  should  be  scrupulously  remembered,  that 
timber  will  not  certainly  remain  sound  because 
a  large  portion,  or  even  most  of  it,  is  in  proper 
condition,  and  well  cared  for.  Only  so  much  as  is 
actually  protected  will  retain  its  qualities ;  and  any 
part  so  exposed  as  to  injure  the  whole  stick  will 
as  surely  injure  or  destroy  the  unprotected  part. 
Therefore,  the  ends  of  timbers  which  are  built  into 
walls,  also  all  surfaces  in  contact,  —  as  where  the 
side  or  edge  of  one  stick  rests  upon  another,  tenons 
in  mortises,  &c.,  —  should  be  supplied  with  air, 
kept  dry,  and  in  every  way  properly  protected. 


DURABILITY  OF  TIMBER. 

The  durability  of  timber   is   almost   incredible. 
The  following  are  a  few  examples  for  illustration, 


THE    PRESERVATION    OF    TIMBER.  39 

being  vouched  for  by  Buffon,  Du  Hamel,  Rondelet, 
and  others  :  — 

The  piles  of  a  bridge  built  by  Trajan,  after  hav- 
ing been  driven  more  than  sixteen  hundred  years, 
were  found  to  be  petrified  four  inches ;  the  rest 
of  the  wood  being  in  its  ordinary  condition. 

The  elm-piles  under  the  piers  of  London  Bridge 
have  been  in  use  more  than  seven  hundred  years, 
and  are  not  yet  materially  decayed. 

Beneath  the  foundation  of  Savoy  Place,  Lon- 
don, oak,  elm,  beach,  and  chestnut  piles  and  planks 
were  found  in  a  state  of  perfect  preservation,  after 
having  been  there  for  six  hundred  and  fifty  years. 

While  taking  down  the  old  walls  of  Tunbridge 
Castle,  Kent,  there  was  found,  in  the  middle  of  a 
thick  stone  wall,  a  timber-curb,  which  had  been 
enclosed  for  seven  hundred  years. 

Some  timbers  of  an  old  bridge  were  discovered, 
while  digging  for  the  foundations  of  a  house  at  Dit- 
ton  Park,  Windsor,  which  ancient  records  incline  us 
to  believe  were  placed  there  prior  to  the  year  1396. 

The  durability  of  timber  out  of  the  ground  is 
even  greater  still.  The  roof  of  the  basilica  of 
St.  Paul,  at  Rome,  was  framed  in  the  year  816; 
and  now,  after  more  than  a  thousand  years,  it  is 
still  sound :  and  the  original  cypress-wood  doors 


40  THE   PRESERVATION    OF    TIMBER. 

of  the  same  building,  after  being  in  use  more 
than  six  hundred  years,  were,  when  replaced  by 
others  of  brass,  perfectly  free  from  rot  or  decay ; 
the  wood  retaining  its  original  odor.  The  timber- 
dome  of  St.  Mark,  at  Venice,  is  still  good,  though 
more  than  eight  hundred  and  fifty  years  old.  The 
roof  of  the  Jacobin  Convent  at  Paris,  which  is 
of  fir,  was  executed  more  than  four  hundred  and 
fifty  years  ago. 

The  age  of  our  country's  settlement  does  not 
enable  us  to  refer  to  examples  of  like  antiquity; 
but  no  good  reason  appears  to  exist  why  timber 
may  not  be  as  durable  in  America  as  in  Europe. 
Many  old  white-pine  cornices  here  exist,  which, 
having  been  kept  properly  painted,  have  been  ex- 
posed to  the  storms  of  more  than  a  hundred  and 
fifty  years.  The  wood  is  still  sound,  and  the 
arrises  are  as  good  as  when  they  were  made ; 
while  freestone,  in  the  same  neighborhoods,  has 
decayed  badly  in  less  than  fifty  years. 


STRENGTH  OF   TIMBER. 


To  discover  rules  which  will  in  all  cases  determine 
the  exact  strength  of  timber  has  for  many  years 
been  an  object  of  interest  with  scientific  men.  Mr. 
Tredgold,  an  eminent  writer  on  the  science  of  car- 
pentry, has  laid  down  at  length  the  results  of  the 
best  investigations  made  by  himself  and  others ; 
but,  in  summing  up,  he  speaks  as  follows:  "The 
age  of  trees  at  the  time  of  cutting ;  the  natural 
defects,  such  as  knots,  shakes,  &c. ;  also  the  mode 
of  seasoning,  or  the  comparative  dryness, —  are 
the  cause  of  some  difference  in  the  strength  and 
stiffness  of  timber.  All  these  things  considered,  it 
is  impossible  to  calculate  correctly  its  strength  and 
stiffness."  After  reminding  the  reader  that  the 
"  precision  which  is  so  essential  to  the  philosopher 
is  not  absolutely  necessary  to  the  architect  and 
engineer,"  he  says,  "  They  content  themselves  with 
approximations  that  are  simple  and  easy  to  be 


42  STRENGTH    OF    TIMBER. 

obtained ;  and,  provided  that  the  limits  which  can- 
not be  passed  with  safety  be  pointed  out,  these 
approximations  are  sufficient  to  direct  their  prac- 
tice." * 

Mr.  Peter  Nicholson  (from  whose  works  subse- 
quent authors  have  borrowed  ad  libitum)  remarks 
as  follows :  "  On  that  subtile  subject,  —  the  propor- 
tional strength  of  timber,  on  which  I  gave  some 
observations  and  calculations  in  my  '  Carpenter's 
Guide,'  —  I  was  in  hopes  that  I  should  have  been 
able  to  reduce  the  theory  of  scantlings  to  an  arith- 
metical rule  of  consequences  certain,  and  of  general 
application.  I  have  to  lament  that  all  my  endea- 
dors,  assisted  by  several  gentlemen  well  versed  in 
mathematics,  have  hitherto  been  unsuccessful."  t 

Experiments  on  the  strength  of  timber  have, 
until  a  late  day,  tended  but  little  to  reform  the 
science  of  carpentry.  Probably  more  has  been 
done  by  bold,  and  perhaps  rash,  experiments  than 
by  all  the  works  which  have  been  written.  It 
remains  a  fact,  however,  that  the  strength  of  any 
piece  of  timber  may  be  determined  with  sufficient 
accuracy  for  all  practical  purposes.  In  the  ex- 

*  Tredgold's  "  Elementary  Principles  of  Carpentry,"  art.  68, 
p.  29. 

t  "  Carpenter  and  Joiner's  Assistant,"  pp.  vi.  and  vii.  (Pre- 
face). 


STRENGTH    OF    TIMBER.  43 

amples  of  framing  published  in  this  work,  such 
dimensions  for  the  several  timbers  are  given  as 
experience  has  approved ;  and  these  examples 
comprise  all  that  any  carpenter  can  need.  But, 
that  he  may  be  fully  informed  in  regard  to  the 
strength  of  the  various  kinds  in  common  use,  tables 
and  rules  will  be  given,  exhibiting  the  principles 
involved.  These  tables  have  been  prepared  ex- 
pressly for  this  work,  and  are  founded  on  the 
results  of  many  experiments  made  on  dry  and 
sound  wood,  grown  in  either  Massachusetts,  New 
Hampshire,  or  Maine.  The  specimens  were  se- 
lected as  a  just  average  of  the  respective  kinds ; 
and,  as  the  experiments  were  carefully  made,  the 
tables  may  be  considered  as  reliable. 


TIMBER-STRAINS. 


TIMBER  may  be  subjected  to  three  kinds  of 
strain :  — 

IsZ,  When  the  force  tends  to  pull  the  piece  in 
the  direction  of  its  length :  this  is  called  tensile 
strain. 

2d,  When  the  force  tends  to  bend  it  in  the  direc- 
tion of  its  depth,  or  across  the  fibres :  this  is  com- 
monly known  as  cross-strain. 

3d,  When  it  tends  to  compress  it  in  the  direction 
of  its  length,  or  what  is  called  compressive  strain. 


TENSILE  STEAIN. 


The  following  table  exhibits  the  tensile  strength 
of  an  inch-square  rod  of  each  of  the  kinds  of  wood 
in  common  use  ;  or,  in  other  words,  the  power  each 


TIMBER-STRAINS.  45 

will  resist  when  so  applied  as  to  tend  to  tear  it 
asunder  in  the  direction  of  its  length :  — 

Kind  of  Wood.  Weight  in  Pounds. 

Black  Spruce 10,260 

White  Pine 8,300 

Carolina  Pine 12,000 

White  Oak 13,200 

Hemlock 9,100 

Chestnut 10,500 


PROBLEM    I. 

TO  DETERMINE  THE  TENSILE  STRENGTH  OF  A  RECTANGULAR 
TIMBER. 

RULE.  —  Multiply  the  thickness  of  the  piece  in 
inches  by  its  depth  *  in  inches,  and  the  product  by  the 
weight  set  against  the  kind  of  wood  in  the  table.  The 
product  so  obtained  will  be  the  force  in  pounds  the 
piece  will  resist. 

EXAMPLE.  —  What  force  will  be  required  to  pull 
asunder  a  tie-beam  of  spruce,  7  inches  thick  and  10 
inches  deep? 

Thickness,     7  10,260  Breaking-power. 

Depth,        10  70 

70     Ans.  718,200  Ibs. 

*  The  distance  across  the  top  of  the  beam,  when  it  is  in  a 
horizontal  position,  is  commonly  called  its  thickness;  and  that 
of  the  side,  from  the  top  to  the  tinder  part,  its  depth. 


46  TIMBER  STRAINS. 


PROBLEM    II. 

TO  DETERMINE  THE  DIMENSIONS  OF  A  PIECE  OF  TIMBER 
THAT  WILL  RESIST  A  GIVEN  STRAIN,  ONE  SIDE  ONLY 
BEING  GIVEN. 

RULE.  —  Multiply  the  sum  set  against  the  kind  of 
wood  in  the  table  by  the  given  side  in  inches,  and  divide 
the  force  to  be  resisted  by  this  product.  The  quotient 
will  be  the  dimension,  in  inches,  of  the  side  required. 

EXAMPLE.  —  What  must  be  the  depth  of  a  beam  of 
white  pine,  4  inches  thick,  to  resist  a  strain  of  232,400 
pounds  ? 

8,300  Breaking-weight.  33,200)  232,400  (7  inches. 

4  Thickness.  232,400 


33,200  Ans.  4  by  7  inches. 


The  following  table  exhibits  the  tensile  strength 
of  various  kinds  of  wood,  as  given  by  the  authors 
named  :  — 


Kind  of  Wood.  SqYncMnms.  Experimentalist. 

English  Oak  ......  19,800  .....  Bevan. 

„          „      ......  17,300  .....  Muschenbrock. 

Beech    .........  22,000  .....  Bevan. 

„        .........  17,300  .....  Muschenbrock. 

Ash    ..........  16,700  .....  Bevan. 

„       ..........  12,000  .....  Muschenbrock. 

Elm    ..........  14,400  .....  Bevan. 

„       ..........  13,489  .....  Muschenbrock. 


TIMBER-STRAINS.  4)7 

Locust 16,000 Bevan. 

„       20,582 Muschenbrock. 

Walnut 7,800 Bevan. 

„        8,130 Muschenbrock. 

Poplar 7,200 Bevan. 

„       6,641 Muschenbrock. 

Pitch-Pine 7,818 Muschenbrock. 

Larch 8,900 Bevan. 

Teak 8,200 Bevan. 

Mahogany 21,800 Bevan. 

Lancewood 23,400 Bevan. 


The  following  corollaries,  in  relation  to  the 
strength  of  timber,  have  been  established  by  ex- 
periment :  — 

1st,  A  piece  of  timber  should  not  be  subjected 
to  a  permanent  strain  of  more  than  a  fourth  of  the 
power  that  would  break  it. 

2«/,  A  piece  of  perfect  timber,  while  in  a  level 
position  and  properly' supported,  is  supposed  to  be 
of  equal  tensile  strength  throughout ;  and,  whether 
the  piece  be  long  or  short,  it  is  liable  to  part  in 
one  place  nearly  as  quick  as  in  another. 

3d,  A  piece  of  perfect  timber,  in  a  vertical  po- 
sition, is  in  tensile  strength  proportionate  to  its 
length ;  a  short  piece  being  stronger,  since  a  long 
one  must,  in  addition  to  the  power  applied  to  the 


48  TIMBER-STRAINS. 

lower  end,  sustain  its  own  weight ;  and  hence, 
when  it  breaks,  will  part  near  the  top. 

4th,  In  calculating  the  strength  of  any  piece  of 
timber,  only  so  much  of  the  wood  should  be  mea- 
sured as  is  continued  throughout  the  entire  stick. 
For  instance,  a  tie-beam  measuring  eight  by  ten 
inches,  having  an  inch-and-a-half  rod  passing 
through  it,  should  be  considered  as  measuring  but 
six  inches  and  a  half  thick  ;  and  if  the  ends  of 
struts,  or  any  thing  of  the  kind,  be  cut  down,  into 
and  across  the  top  of  the  beam,  two  inches,  it  would 
then  measure  but  eight  inches  deep. 

5th,  A  rectangular  beam  supported  at  both  ends, 
with  its  diagonal  placed  vertically,  will  thereby  be 
reduced,  in  cross-strength,  one-tenth. 

6th,  The  tough  and  hard  woods,  as  oak  and 
chestnut,  are  about  an  eighth,  and  the  soft  ones,  as 
spruce,  pine,  and  hemlock,  from  a  sixteenth  to  a 
twentieth,  as  strong,  when  the  power  is  applied  at 
right  angles  to  the  fibres,  as  when  applied  to  their 
length.  This  power  is  that  which  a  pin  exerts  on 
the  wood  of  a  post  through  which  it  has  been 
driven,  when  the  tenon,  which  is  pinned  in,  tends 
to  drag  it  out,  and  thereby  split  the  wood. 


49 


CROSS-STRAIN. 


WHEN  a  piece  of  timber  is  supported  only  at  the 
ends,  and  a  weight  or  power  is  applied  at  the 
centre,  it  will,  if  the  force  is  sufficient,  bend  or  sag. 
If  the  power  of  resistance  be  great,  the  wood  is 
said  to  be  stiff ;  but,  if  it  bends  easily,  it  is  said  to 
be  flexible.  Should  it  bend  much,  without  fracture, 
it  is  called  tough. 

If  a  beam,  two  feet  long  and  an  inch  square, 
will  support,  at  its  centre,  five  hundred  pounds, 
one  of  the  same  length,  two  inches  wide  and  an 
inch  deep,  will  support  a  thousand  pounds.  Hence 
we  have  as  a  rule,  that  beams  of  the  same  depth  are 
to  each  other  as  their  thickness.  Should  the  beam 
described  be  turned  upon  its  side,  so  as  to  make  it 
an  inch  thick  and  two  inches  deep,  it  will  support 
two  thousand  pounds.  "We  therefore  have  as  a 
second  rule,  that  beams  of  equal  thickness  are  to 
each  other  as  the  square  of  their  depth. 
4 


50  CROSS-STRAIN. 

If  a  beam,  an  inch  square  and  two  feet  long, 
will  support,  at  its  centre,  five  hundred  pounds,  one 
four  feet  long  will  support  but  two  hundred  and 
fifty  pounds.  A  third  rule,  therefore,  is,  that  learns 
are  to  each  other  inversely  as  their  length* 

If  a  beam,  sixteen  feet  long,  supported  at  the 
ends,  will  support,  at  its  centre,  a  weight  of  eight 
hundred  pounds,  it  will  support  equally  well  twice 
that  amount  if  eight  hundred  pounds  be  placed  at 
points,  each  four  feet  from  either  side  of  the 
centre,  —  half-way  between  the  centre  and  the 
points  of  support.  Again :  it  will  equally  well 
support  twice  that  amount  (or  3,200  pounds),  if 
sixteen  hundred  pounds  be  placed  at  points,  each 
half-way  from  those  last  named  and  the  points 
of  support  (two  feet).  A  beam,  therefore,  that 
will  support  a  thousand  pounds  at  its  centre,  will 
support  two  thousand  pounds  if  the  weight  be 
distributed  equally  over  its  entire  length. 

A  beam,  having  but  one  end  fixed  in  a  wall, 
will  sustain  only  a  fourth  as  much  weight,  when 
applied  to  the  end,  as  will  one  of  the  same  dimen- 

*  Experiments  made  by  Bufibn  tend  to  prove  that  the 
strength  of  a  beam  does  not  decrease  in  exact  geometrical 
progression  to  its  length,  but  that  it  will  actually  bear  some- 
thing more  than  half  the  amount  which  would  break  one  of 
half  its  length. 


CROSS-STRAIN.  51 

sions  with  both  ends  in  like  manner  supported,  and 
the  weight  placed  at  the  middle.  When  the  weight 
is  equally  distributed  over  the  entire  length  of  a 
beam  which  has  only  one  end  supported,  it  will 
sustain  twice  the  amount  that  would  break  it  if 
applied  to  the  middle. 

Should  three  beams  be  fixed  at  one  end  in  a 
wall,  and  the  other  end  left  unsupported,  —  one 
of  them  inclined  upwards,  one  at  the  same  angle 
downwards,  and  the  third  level  or  at  right  angles 
with  the  wall,  —  that  inclined  upwards  would  sus- 
tain the  least  weight ;  that  inclined  downwards,  the 
most ;  and  the  horizontal  one,  a  mean  between 
the  two.  In  calculating  the  strength  of  an  inclined 
beam,  the  distance  from  the  end  of  the  beam,  at 
right  angles  with  the  wall,  should  be  taken  as  the 
actual  length  of  the  beam ;  which  length,  as  a 
basis,  will  give  the  strength  of  the  beam,  if,  instead 
of  being  inclined,  it  were  placed  hi  a  horizontal 
position. 

From  the  foregoing  data,  it  will  be  seen,  that, 
by  the  aid  of  tables  and  rules,  it  is  easy  to  deter- 
mine the  strength  of  inclined  as  well  as  horizon- 
tal timbers. 

The  following  table  exhibits  the  cross-strength 
of  each  of  the  several  kinds  of  wood ;  the  pieces 


52  CROSS-STRAIN. 

being  dry,  an  inch  square,  and  twelve  inches  long 
between  the  points  of  support :  — 

Wood.  Breaking-weight  in  Ibs. 

Black  Spruce 590 

White  Pine 548 

Carolina  Pine 684 

White  Oak 738 

Hemlock 426 

Chestnut .  595 


PROBLEM    III. 

TO  DETERMINE  THE   CROSS-STRENGTH   OF   A   STICK   OF 
TIMBER. 

RULE.  —  Multiply  the  thickness  of  the  stick  in 
inches  by  the  square  of  its  depth  in  inches,  and  divide 
the  product  by  the  length  of  the  piece  in  feet.  With 
the  quotient  multiply  the  sum  in  the  table  that  is  set 
against  the  kind  of  wood ;  and  the  product  will  be  the 
breaking-weight  in  pounds. 

EXAMPLE.  — What  weight  will  a  spruce-beam,  18  feet 
long,  6  inches  thick,  and  8  inches  deep,  sustain  ? 


Length. 

Breaking-weight. 

8  Depth. 

18)384(21.3 

590 

8 

36 

21.3 

64  Square. 

24 

177.0 

6  Thickness. 

18 

590 





1180 

384 

60 



54 

12,567.0  Ibs. 

CROSS-STRAIN.  53 


PROBLEM    IV. 

TO  DETERMINE  THE  DEPTH  OF  A  STICK  OF  TIMBER  THAT 
WILL  SUSTAIN  A  GIVEN  WEIGHT,  THE  THICKNESS  AND 
LENGTH  BEIXG  GIVEN. 

RULE.  —  Divide  the  weight  to  be  sustained  by  the 
sum  set  against  the  kind  of  wood  in  the  table.  Mul- 
tiply the  quotient  by  the  length  of  the  stick  in  feet,  and 
divide  the  product  by  the  thickness  of  the  stick  in 
inches.  The  square-root  of  the  quotient  will  be  the 
depth  of  the  stick  in  inches. 

EXAMPLE.  —  What  depth  will  be  required  to  a  stick 
of  chestnut,  19  feet  long  and  3  inches  thick,  that  it  may 
sustain  27,251  pounds? 

Breaking- 
weight.  .       .     . 

595)27251(45.8        45.8       290.066(5.38 
2380  19  Length.  25 

3451  4122   -  103)  400 

2975  458          309 


4760  Thickness  3)  870.2     1068)  9166 
4760  8544 

290.066 

Ans.  5T3QS5  inches  nearly. 


54  CROSS-STRAIN. 


PROBLEM    V. 

TO  DETERMINE  THE  THICKNESS  OF  A  STICK  OF  TIMBER 
THAT  WILL  SUSTAIN  A  GIVEN  WEIGHT,  THE  LENGTH 
AND  DEPTH  BEING  GIVEN. 

RULE. — Divide  the  weight  to  be  sustained  by  the 
sum  set  against  the  kind  of  wood  in  the  table.  Multi- 
ply the  quotient  by  the  length  of  the  stick  in  feet,  'and 
divide  the  product  by  the  square  of  the  depth  in  inches. 
The  quotient  will  be  the  thickness  of  the  beam  in 
inches. 

EXAMPLE.  —  What  should  be  the  thickness  of  a 
hemlock-beam,  21  feet  long  and  12  inches  deep,  that  it 
may  sustain  a  weight  of  19,170  pounds? 

Breaking-weight. 

426)19170(45  45  12  Depth. 

1704  21  Length.       12 

2130  45  144  Square. 

2130  90 

144)  945  (£.56 
864 

810 
720 

900 
864 

Ans.  6I5J3_  inches  nearly. 

The  following  table  exhibits  the  breaking-weight 
of  various  kinds  of  wood  as  given  by  the  authors 
therein  named :  — 


CROSS-STRAIN. 


55 


Experiments  on  the  Strength  of  Woods. 


END  OP  WOOD. 

Length  In  Feet. 

° 

1 

1 

1 

IDr  flrctlon  In 
Incites  in  the 
time  of  fracture. 

Welpht  in  Pounds 
that  l.roke  the 
piece. 

! 

English  Oak,  young  tree 
Oak,  old  ship-timber  .  .  . 
,,     from  old  tree   .... 
,,     medium  quality    .  . 
Green  Oik       

2 

2.5 
2 
2.5 
2.5 

1 
1 
1 

1 

1 

1 
1 
1 

187 

1.5 
1.38 

482 

264 
218 
284 
219 

Tredgold. 
Ebbels. 

Otk  from  Riga 

2 

1 

1 

1.25 

357 

Tredgold. 

Green  Oak  

11.75 

85 

85 

3.2 

25S12 

Buffon. 

Beech,  medium  quality  . 
Alder  

2.5 
2.5 

1 
1 

1 
1 

271 
212 

Ebbela. 

Plane-tree  

2.5 
2.5 

1 
1 

1 

1 

243 
214 

» 

2.5 

1 

1 

180 

Ash,  from  young  tree  .  . 
\sh  .  .  . 

25 
25 

1 
1 

1 

1 

2.5 

2.38 

324 
314 

Tredgold. 

Common  Elm  
Green  Witch-Elm    .... 
,,      Acacia  
Sp.  Mahogany,  seasoned  . 
Hond.     „                „ 
Green  Walnut    

25 
2.5 
2.5 
25 
2.5 
2.5 

1 
1 
1 
1 
1 
1 

1 

1 
1 
1 
1 
1 

116 
192 
249 
170 
255 
195 

Ebbe'ls. 

Tredgold. 
Ebbek 

Lombardy  Poplar  .... 
Abele  Poplar  
Teak  

2.5 
2.6 

1 

1 
fl 

1 
1 
?. 

1.5 
4.0 

131 
228 
820 

Tredgold. 
Barlow. 

Willow 

•>5 

1 

1 

30 

146 

Tred°'old 

Birch  .  .  .  .  -  

25 

1 

1 

2(>7 

Ebbels. 

Cedar  of  Libanfls,  dry  .  . 
Riga  Fir  

2.5 
25 

1 
1 

1 
1 

2.75 
13 

165 
212 

Tredgold. 

MemelFir  
Norway  Fir.  fr.  Long  Sd. 
Mar-Forest  Fir 

2.5 
2 

1 

1 

9 

1 
1- 

9, 

115 
1.125 
55 

218 
396 
360 

»> 
Barlow 

Scotch  Fir,  Engl.  growth 

Christiania  white  Deal  .  . 
American  white  Spruce    . 
Spruce-fir,  British  growth 
American  Pine,  Weymouth 
Larch,  choice  specimen    . 
,)      medium  quality   . 
„      yery  young  wood  . 
Ri°u  Fir 

25 
2.5 
2 
2 
2.5 
2 
2.5 
2.5 
•2:, 
4 

1 

1 
1 
1 
1 
1 
1 
1 
1 
S 

I 
1 
1 
1 
1 
1 
1 
1 
1 
ft 

1.75 

0937 
1.312 

1125 
3.0 

1.75 

233 
157 
343 
285 
186 
329 
253 
223 
129 
4530 

Tredgold. 
Ebbels. 
Tredgold. 

Ebbels. 
Tredgold. 

Red  Pine  

4 

3 

3 

3780 

Yellow  Pine  . 

4 

^ 

ft 

2756 

Cowrie  
Poona  

4 
,  4 

IS 
3 

3 

3 

4110 
3990 

56  CROSS-STRAIN. 

It  has  been  decided  by  experiment,  that  a  fifth 
of  the  breaking-weight  will  cause  deflection,  in- 
creasing with  time,  and  ultimately  producing  a 
permanent  set.  By  an  examination  of  the  table, 
it  will  be  discovered  that  wood  of  old  trees  is  much 
weaker  than  that  of  those  of  mean  age ;  also  that 
timber  is  stronger  as  it  is  heavier,  though  the  in- 
crease in  all  examples  is  not  exactly  proportionate 
to  its  solidity. 


57 


COMPRESSION. 


COMPRESSION  is  the  power  exerted  on  a  post  when 
loaded  with  a  superincumbent  weight,  as  that  which 
is  exerted  on  the  collar-beam,  or  struts  and  rafters 
of  a  truss. 

It  has  been  discovered,  that  a  timber,  if  placed 
as  a  post,  whether  long  or  short,  would  in  either 
case,  if  entirely  inflexible,  support  a  weight  equally 
well.  But,  inasmuch  as  there  is  some  flexibility 
in  aU  timber,  a  piece  will,  if  higher  than  about 
seven  times  its  diameter,  bend  and  break  before 
it  can  be  crushed  by  compression ;  and  it  is  stated, 
that  a  piece,  if  a  hundred  times  as  high  as  it  is 
in  diameter,  will  be  incapable  of  supporting  the 
smallest  weight* 

The  nature  of  the  subject  under  consideration 
makes  it  next  to  impossible  to  determine  rules 
which  will  be  of  much  service.  As  the  compres- 

*  Gwilt's  "  Encyclopaedia  of  Architecture,"  p.  442,  art.  1600. 


58  COMPRESSION. 

sive  strength  of  timber  is  so  variable  in  different 
specimens,  and  in  none  so  geometrically  propor- 
tionate to  its  length  as  to  give  reliablfe  data,  rules 
for  ascertaining  the  exact  size  for  all  purposes  and 
situations  would  only  confuse,  if  not  deceive,  the 
mechanic. 

The  power  of  resistance  to  compression  is  so 
great,  that  no  serious  danger  need  be  apprehended 
from  the  use  of  such  dimensions  of  timber  for 
collar-beams,  truss-rafters,  struts,  &c.  (these  being, 
when  in  use,  in  a  state  of  compression),  as  will 
generally  agree  with  the  tie-beams  and  purlins ; 
and  the  only  rule  that  may  be  considered  of  value 
is,  that  the  compressed  pieces  of  any  work  should 
bear  such  a  proportion  to  those  subjected  to  a 
tensile  or  cross  strain  as  will  make  the  whole  truss, 
whatever  its  design,  comparatively  uniform  in  ap- 
pearance throughout. 

The  following  table,  prepared  by  Mr.  Tredgold, 
was  designed  to  aid  in  determining  the  strength  of 
timber  when  compressed  in  the  direction  of  its 
length.  The  calculations  were  made  for  foreign 
timber.  It  is  presumed,  however,  they  are  quite 
as  reliable  for  timber  grown  in  America  as  for  that 
grown  in  England,  since  in  neither  is  their  truth 
susceptible  of  mathematical  demonstration. 


COMPRESSION.  59 

Kind  of  Wood.  Proportional  Strength. 

English  Oak 0015 

Beech 00195 

Alder 0023 

Green  Chestnut 00267 

Ash 00168 

Elm 00184 

Locust 00152 

Riga  Fir 0015,2 

MemelFir 00133 

Norway  Spruce    .     .   -.     .     .     .     .00142 

White  Pine .00157 

Larch  .0019 


PROBLEM    VI. 

TO  DETERMINE  THE   DIAMETER  OF  A   ROUND    COLUMN   THAT 
WILL   SUPPORT  A   GIVEN  WEIGHT. 

RULE.  — Multiply  the  weight  in  pounds  by  1.7  times 
the  amount  set  against  the  land  of  wood  in  the  table ; 
then  multiply  the  square-root  of  the  product  by  the 
length  or  height  in  feet ;  and  the  square-root  of  the 
last  product  will  be  the  diameter  of  the  post  in  inches. 

If  the  column  be  shorter  than  ten  times  its 
diameter,  the  dimensions  ascertained  by  this  rule 
will  be  too  small ;  in  which  case,  the  true  diameter 
may  be  determined  by  Problem  VIII. 


60  COMPRESSION. 


PROBLEM    VII. 

TO    DETERMINE   THE    SIZE    OF    A    RECTANGULAR    POST    THAT 
WILL,  SUPPORT   A   GIVEN   WEIGHT. 

RULE.  —  Multiply  the  weight  in  pounds  by  the 
square  of  the  length  of  the  post  in  feet,  and  this 
product+by  the  number  set  against  the  kind  of  wood 
in  the  table.  Divide  the  product  by  the  breadth  in 
inches,  and  the  cube-root  of  the  quotient  will  be  the 
thickness  in  inches. 

In  case  the  post  is  less  than  ten  diameters  high, 
the  dimensions  will  be  determined  by  Problem 
VIII.,  as  before  directed. 


RESISTANCE  TO   CRUSHING. 

According  to  Rennie's  experiments,  the  power 
of  wood  to  resist  crushing  (a  cube  an  inch  square 
being  used,  and  the  power  applied  to  the  end  of 
the  grain)  is  as  follows*-:  — 

Kind  of  Wood.  Resistance. 

Elm 1284 

American  Pine 1606 

White  Deal 1928 

English  Oak 3860 


COMPRESSION.  61 


PROBLEM    Vffl. 

TO  DETERMINE  THE  LOAD  ANY  POST  OF  LESS  THAN  TEN 
TIMES  ITS  DIAMETEK  IN  HEIGHT  WILL  SUPPORT  WITH- 
OUT CRUSHING. 

RULE.  —  Multiply  the  area  of  the  post  in  inches  by 
the  weight  that  will  crush  a  square-inch  of  the  kind 
of  wood.  A  fourth  of  the  product  is  the  greatest 
permanent  load  the  post  will  bear  with  safety. 

Only  two  other  strains  to  which  wood  may  be 
subjected  need  be  noticed. 

One  is  that  exerted  by  the  foot  of  a  truss,  rafter, 
or  any  thing  of  the  kind,  on  the  wood  between  it 
and  the  end  of  the  tie-beam  on  which  it  stands ; 
the  tendency  being  to  slide,  or  push  off  the  wood. 
The  quality  which  resists  this  is  called  the  lateral 
adhesion.  Experiments  have  proved  that  the  soft 
woods,  as  spruce,  pine,  &c.,  will  resist  a  force 
of  from  five  to  seven  hundred  pounds,  and  the 
hard  woods,  as  oak  and  chestnut,  from  six  to  nine 
hundred  pounds,  to  the  square-inch.  As  no  piece 
of  good  carpentry  would  be  dependent  on  the 
simple  adhesion  of  the  wood  alone  for  support, 
but,  where  the  thrust  is  one  of  more  than  ordinary 
moment,  bolts  or  straps  should  be  employed,  rules 
and  further  suggestions  are  uncalled  for. 


62  COMPRESSION, 

The  other  strain  to  which  reference  has  been 
made  is  where  the  power  tends  to  tear  asunder  the 
fibres  of  the  wood  in  the  direction  of  their  length. 
(See  corollary  6,  page  48.)  Experiments  made 
on  oak  and  chestnut  show  this  resistance  to  be 
from  nineteen  hundred  and  fifty  to  twenty-six 
hundred  pounds  to  the  square-inch,  and  white  pine 
and  spruce  from  six  hundred  and  fifty  to  twelve 
hundred  pounds. 


GEOMETRY  AND  SQUARE-ROOT. 


65 


GEOMETRY. 


"  GEOMETRY  is  the  foundation  of  architecture,  and 
the  root  of  mathematics."  Such  being  the  case, 
a  knowledge  of  its  leading  principles  is  essential 
to  a  successful  practice  of  the  art  of  carpentry. 
While  only  a  part  of  the  science  is  necessarily 
called  into  requisition,  that  part  is  all-important. 

It  is  presumed  that  every  apprentice  will  make 
himself  familiar  with  the  science  by  the  study  of 
some  good  treatise  on  the  subject.  A  few  rules, 
however,  for  making  calculations  will  be  given 
in  this  work.  They  are  introduced,  as  in  other 
cases  of  like  nature,  more  for  the  purpose  of 
refreshing  the  memory  than  for  imparting  original 
information. 

The  diagrams  on  Plate  I.  exhibit  such  general 
principles  as  are  most  frequently  used  by  the  car- 
penter ;  and  it  is  believed  they  will  convey  all  the 
information  he  may  require. 
5 


66  GEOMETRY. 


PLATE     I. 

FIG.  1.  —  To  draw  a  line  perpendicular  to  another 
at  a  given  point. 

From  the  points  A  and  C,  equally  distant  from  the 
given  point  B,  with  the  radius  AC  describe  arcs  in- 
tersecting each  other  at  D.  From  this  point  to  B  draw 
the  line  DB,  which  will  be  the  line  required. 

FIG.  2.  —  To  draw  a  line  perpendicular  to  another 
at  its  extremity. 

Let  B  represent  the  extremity  of  the  line.  From  any 
point  above  the  line  AB,  as  a  centre,  describe  the  arc 
DBA.  Draw  AD  from  the  point  where  the  arc  cuts  the 
line  AB.  Through  the  centre  C,  and  from  the  point 
where  AD  cuts  the  arc,  draw  the  line  DB,  which  will  be 
the  line  required. 

FIG.  3.  —  To  draw  an  equilateral  triangle  to  any 
given  base. 

Let  AB  represent  the  base.     From  the  points  A  and 

B,  with  the  radius  AB  describe  arcs  cutting  each  other  at 

C.  From  C,  draw  the  lines  CA  and  CB,  which  produce 
the  triangle  required. 

FIG.  4.  —  To  construct  a  square  of  any  given  di- 
mensions. 

Let  AB  represent  the  given  side.  From  A  and  B,  as 
centres,  describe  the  arcs  AD  and  BC.  From  E,  the 
point  of  intersection,  set  off  EC  and  ED  equal  to  EF, 


" 

\ 


A' 


Kig.G. 


-I) 


GEOMETRY.  67 

which  are  one-half  the  line  EA;    then  draw  from  the 
points  the  figure  CABD. 

FIG.  5.  —  To  describe  a  regular  octagon,  or  figure 
of  eight  equal  sides,  of  a  given  dimension. 

Let  AD  represent  the  diameter  of  the  octagon.  From 
this,  draw  the  figure  ADBC;  then  draw  the  diagonals 
AB  and  CD.  With  the  radius  AE,  on  the  points  ADBC, 
describe  arcs  cutting  the  square.  From  the  points  of 
intersection,  draw  diagonals,  and  the  octagon  is  formed. 

FIG.  6.  —  To  draw  a  regular  hexagon  or  triangle 
within  a  given  circle. 

Apply  the  radius  of  the  circle  six  times  around  the 
circumference,  as  at  AB ;  and  the  line  is  a  side  of  the 
hexagon.  Draw  a  line  from  the  points  AC,  and  the  line 
is  the  side  of  an  equilateral  triangle. 

FIG.  7  exhibits  a  method  for  finding  the  centre  of  a 
circle  when  an  arc  is  given ;  also  for  describing  a  seg- 
ment of  a  given  height. 

Let  AB  represent  the  base,  and  dC  the  height.  Pro- 
duce the  lines  AC  and  CB.  On  the  points  A  and  B,  with 
a  radius  of  more  than  half  the  line  AC  describe  the  arcs 
ef  and  gh.  On  the  point  C,  with  the  same  radius,  de- 
scribe the  arcs  ij  and  kl.  Through  the  points  of  inter- 
section, draw  the  lines  mn  and  no,  cutting  each  other  at 
the  point  n ;  which  will  be  the  centre  required. 

FIG.  8.  —  To  inscribe  in  a  circle  a  regular  pentagon, 
or  figure  of  five  equal  sides. 

Draw  two  lines,  AB  and  CD,  perpendicular  to  each 
other.  Divide  the  radius  Ab  into  equal  parts,  as  at  a. 


68  GEOMETRY. 

On  a  as  a  centre,  with  the  radius  «C  describe  the  arc 
Cc  ;  then,  on  B  as  a  centre,  with  the  radius  Be  de- 
scribe the  arc  cd,  and  from  the  point  of  intersection  d 
to  C  will  be  a  side  of  the  pentagon.  A  decagon,  or 
figure  of  ten  sides,  is  described  by  drawing  the  lines  fg 
and  gC,  and  then  proceeding  thus  with  each  of  the  five 
sides  till  the  figure  required  is  completed. 

FIG.  9.  —  This  figure  exhibits  a  method  of  deter- 
mining the  dimensions  and  form  of  a  rectangular 
stick  of  timber  cut  from  a  round  stick,  ivhich  shall 
be  capable  of  supporting  the  greatest  weight  when 
lying  in  a  horizontal  position. 

The  circle  represents  the  outline  of  the  log  or  stick, 
and  ABDC  the  stick  to  be  cut  therefrom.  To  determine 
which,  divide  the  line  AD  (the  diameter  of  the  log)  into 
three  equal  parts.  On  the  points  e  and  f  erect  perpen- 
diculars ;  which  produced,  cut  the  circumference  at  the 
points  BC ;  which,  together  with  the  points  AD,  give 
the  corners  of  the  required  stick. 

FIG.  10.  —  To  describe  an  elliptic  arch  by  inter- 
secting lines,  the  base  and  height  being  given. 

Let  AB  represent  the  base,  and  AC  the  height.  Di- 
vide AC  and  BD  into  any  number  of  equal  parts ;  then 
divide  CD  into  two  equal  parts,  as  at  E.  Divide  CE 
and  DE  each  into  the  same  number  of  parts  as  AC  and 
BD.  Then,  from  the  points  described,  draw  lines  as 
shown  in  the  figure ;  and  the  points  where  these  intersect 
will  be  the  track  of  the  curve.  Trace  a  line  through 
them,  and  we  have  the  figure  AEB. 


GEOMETRY.  69 

I 


DEFINITIONS. 

The  diameter  of  a  circle  is  a  right  line  drawn  through 
its  centre,  and  terminated  at  each  end  by  the  circumfe- 
rence, as  AB,  fig.  8. 

The  radius  of  a  circle  is  a  right  line  drawn  from  the 
centre  to  the  circumference,  being  half  the  diameter ;  as 
C6,  fig.  8. 

An  arc  of  a  circle  is  any  portion  of  the  circumfe- 
ference ;  as  DB,  fig.  2. 

A  chord  is  a  right  line  joining  the  extremities  of  an 
arc ;  as  AB,  fig.  7. 

A  segment  is  any  part  of  a  circle  bounded  by  an  arc ; 
as  ABC,  fig.  6. 

A  semicircle  is  half  a  circle ;  as  ACB,  fig.  8. 

A  sector  is  any  part  of  a  circle  bounded  by  an  arc  and 
the  radii ;  as  pus,  fig.  7. 

A  quadrant  is  a  quarter  of  a  circle ;  as  A6D,  fig.  8. 


70  GEOMETRY. 


PROBLEM     I. 

TO  FIND  THE  AKEA  OF  A  PARALLELOGRAM,  WHETHER  IT 
BE  A  SQUARE,  A  RECTANGLE,  A  RHOMBUS,  OR  A  RHOM- 
BOID. 

RULE.  —  Multiply  the  length  by  the  perpendicular 
height,  and  the  product  will  be  the  area. 


PROBLEM    II. 

TO   FIND   THE  AREA  OF   A   TRIANGLE. 

RULE.  —  Multiply   the  base  by  the  perpendicular 
height,  and  half  the  product  will  be  the  area. 


PROBLEM    III. 

TO    FIND    THE    AREA    OF    A    TRIANGLE    WHOSE    THREE    SIDES 
ARE    GIVEN. 

RULE.  —  From  the  half-sum  of  the  three  sides  sub- 
tract each  side  severally.  Multiply  the  half-sum  and 
the  three  remainders  together,  and  the  square-root 
of  the  product  will  be  the  area  required. 


PROBLEM    IV. 

ANY    TWO    SIDES    OF     A     RIGHT-ANGLED     TRIANGLE     BEING 
GIVEN,   TO    FIND    A    THIRD    SIDE. 

CASE  I.  —  When  two  sides  are  given,  to  find  the  hy- 
pothenuse. 

RULE.  —  Add  the  squares  of  the  two  legs  together,  and 
the  square-root  of  the  sum  will  be  the  hypothenuse. 


GEOMETRY.  71 

CASE  II.  —  The  hypothenuse  and  one  of  the  legs  being 
given,  to  find  the  other  leg. 

RULE.  —  From  the  square  of  the  hypothenuse  take 
the  square  of  the  given  leg,  and  the  square-root  of  the 
remainder  will  be  equal  to  the  other  leg. 


PROBLEM    V. 

TO  FIND  THE  AREA  OF  ANY  REGULAR  POLYGON. 

RULE.  —  Multiply  half  the  perimeter  of  the  figure 
by  the  perpendicular  falling  from  its  centre  upon  one 
of  the  sides,  and  the  product  will  be  the  area  of  the 
polygon.  

PROBLEM    VI. 

TO    FIND    THE   AREA   OF    A    REGULAR    POLYGON,    WHEN    THE 
SIDE   ONLY   IS   GIVEN. 

RULE.  —  Multiply  the  square  of  the  given  side  of 
the  polygon  by  that  number  which  stands  opposite  to 
its  name  in  the  following  table,  and  the  product  will 
be  the  area :  — 

No.  of  Sides.  Names.  Multiplier. 

3  ...  Trigon 0.43301 

4  ...  Tetragon 1.00000 

5  ...  Pentagon 1.72047 

6  ...  Hexagon 2.59807 

7  ...  Heptagon 3.63391 

8  ...  Octagon 4.82842 

9  ...  Nonagon 6.18182 

10  ...     Decagon 7.69420 

11  ...     Undecagon 9.36564 

12  ...    Duodecagon 11.19615 


72  GEOMETRY. 

As  the  foregoing  table  extends  to  five  places 
of  decimals,  it  is  exact  enough  for  all  practical 
purposes. 

PROBLEM    VII. 

THE    DIAMETER    OF    A    CIRCLE    BEING    GIVEN,   TO    FIND    THE 
CIRCUMFERENCE. 

RULE.  —  Multiply  the  diameter  by  22,  and  divide 
the  product  by  1 :  the  quotient  will  be  the  circumfe- 
rence. Or  multiply  the  diameter  by  3,  and  add  a 
seventh  part  of  the  diameter  to  the  product :  the  sum 
will  be  the  circumference  as  obtained  before.  Either 
of  these  methods  is  sufficiently  correct  for  common 
purposes. 


PROBLEM    VIII. 

THE  CIRCUMFERENCE  OF  A  CIRCLE   BEING   GIVEN,  TO   FIND 
THE  DIAMETER. 

RULE.  — Multiply  the  circumference  by  7,  and  divide 
the  product  by  22 :  the  quotient  will  be  the  diameter. 


PR.OBLEM    IX. 

THE   CHORD   AND   HEIGHT  OF   A   SEGMENT   BEING    GIVEN,   TO 
FIND   THE   RADIUS   OF   THE    CIRCLE. 

RULE.  —  To  the  square  of  the  half-chord  add  the 
square  of  the  height,  and  divide  the  sum  by  twice 
the  height  of  the  segment :  the  quotient  will  be  the  ra- 
dius of  the  circle  when  it  is  less  than  a  semicircle. 


GEOMETRY.  73 


PROBLEM    X. 

TO    FIND    THE    AREA    OF    A    CIRCLE,   THE    DIAMETER    BEING 
GIVEN. 

RULE.  —  Multiply  half  the  circumference  by  half 
the  diameter,  and  the  product  will  be  the  area. 


PROBLEM    XI. 

TO   FIND   THE   AREA  OF   A   SECTOR  OF  A   CIRCLE. 

RULE.  —  Multiply  the  radius,  or  half  the  diameter, 
by  half  the  length  of  the  arc  of  the  sector;  and  the 
product  will  be  the  area. 


PROBLEM    XII. 

TO    FIND    THE    AREA    OF    THE    SEGMENT    OF    A    CIRCLE,    THE 
CHORD   AND   HEIGHT  OF  THE   ARC   BEING   GIVEN. 

RULE.  —  To  two-thirds  of  the  product  of  the  base, 
multiplied  by  the  height,  add  the  cube  of  the  height 
divided  by  twice  the  length  of  the  segment ;  and  the 
sum  will  be  nearly  the  area. 


PROBLEM 

TO  FIND  THE  AREA  OF  AN  ELLIPSIS,  THE  TRANSVERSE  AND 
CONJUGATE,  OR  LONG  AND  SHORT,  DIAMETERS  BEING 
GIVEN. 

RULE.  —  Multiply  the  transverse  axis  by  the  conju- 
gate, and  the  product  multiplied  by  .7854  will  be  the 
area. 


74  GEOMETRY. 

PROBLEM    XIV. 

TO   FIND   THE   AREA   OF   A   PRISM. 

RULE.  —  Multiply  the  area  of  the  base,  or  end,  by 
the  perpendicular  height;  and  the  product  will  be  the 
solidity. 


PROBLEM    XV. 

TO   FIND   THE   SOLIDITY   OF   A   PYRAMID. 

RULE.  —  Multiply  the  area  of  the  base,  or  end,  by 
the  perpendicular  height;  and  a  third  of  the  product 
will  be  the  solidity. 

PROBLEM    XVI. 

TO    FIND    THE    SOLIDITY    OF    THE    FRUSTUM     OF    A     SQUARE 
PYRAMID. 

RULE.  —  To  the  rectangle  of  the  sides  of  the  two 
ends  add  the  sum  of  their  squares.  That  sum  being 
multiplied  by  the  height,  a  third  of  the  product  will  be 
the  solidity. 


PROBLEM    XVn. 

TO  FIND   THE   SOLIDITY   OF  A   SPHERE,   OR   GLOBE. 

RULE.  —  Multiply  the  cube  of  the  diameter  by  .5236, 
and  the  product  will  be  the  solidity. 


GEOMETRY.  10 

PROBLEM    XVIU. 

TO   FIND   THE   SOLIDITY   OF   THE    SEGMENT   OF   A    GLOBE. 

RULE.  —  To  three  times  the  square  of  half  the  dia- 
meter of  the  base  of  the  segment  add  the  square  of 
the  height  of  the  same.  Multiply  that  sum  by  the 
height  named,  and  the  product  multiplied  by  .5236 
will  give  the  solidity. 

PROBLEM    XIX. 

TO    FIND    THE    CONVEX    SUPERFICE    OF    A    RIGHT    CYLINDER, 
THE   CIRCUMFERENCE  AND  LENGTH   BEING   GIVES. 

RULE.  —  Multiply  the  circumference  by  the  length, 
and  the  product  will  be  the  area. 


PROBLEM    XX. 

TO    FIND    THE    CONVEX    SUPERFICE    OF    A    RIGHT    CONE,   THE 
CIRCUMFERENCE  AND  SLANT  SIDE  BEING   GIVEN. 

RULE.  —  Multiply  the  circumference  by  the  slant 
side,  and  half  the  product  will  be  the  area. 


PROBLEM    XXI. 

TO  FIND  THE  CONVEX  SUPERFICE  OF  THE  FRUSTUM  OF  A 
CONE,  THE  CIRCUMFERENCES  OF  BOTH  ENDS  AND  THE 
SLANT  SIDE  BEING  GIVEN. 

RULE.  —  Multiply  the  sum  of  the  circumferences  by 
the  slant  side,  and  half  the  product  will  be  the  area. 


76  GEOMETRY. 


PROBLEM     XXII. 

TO    FIND    THE    SUPERFICE    OF    A     SPHERE,    OB    GLOBE,    THE 
CIRCUMFERENCE   BEING   GIVEN. 

RULE.  —  Multiply  the  square  of  the  circumference 
by  .3183,  and  the  product  will  be  the  super/ice. 


PKOBLEM    XXIII. 

TO  FIND  THE  CONVEX  SUPERFICE  OF  THE  SEGMENT  OF  A 
GLOBE,  THE  DIAMETER  OF  THE  BASE  OF  THE  SEGMENT 
AND  ITS  HEIGHT  BEING  GIVEN. 

RULE.  —  To  the  square  of  the  diameter  of  the  base 
add  the  square  of  twice  the  height,  and  the  sum  mul- 
tiplied by  .7854  will  give  the  superjice. 


PROBLEM    XXIV. 

TO  FIND  THE  CONVEX  SUPERFICE  OF  AN  ANNULUS,  OR  RING, 
WHOSE  THICKNESS  AND   INNER  DIAMETER  ARE   GIVEN. 

RULE.  —  To  the  thickness  of  the  ring  add  the  inner 
diameter.  Multiply  the  sum  by  the  thickness,  and  the 
product  multiplied  by  9.869  will  be  the  superjice. 


77 


SQUARE-ROOT. 


As  the  extraction  of  the  square-root  of  numbers  is 
required  to  calculate  the  strength  of  timber,  the 
rule  will  be  given  below,  more  to  refresh  the  me- 
mory than  to  give  original  information  as  to  its 
principles ;  it  being  presumed  that  every  intelligent 
workman  has  made  himself  familiar  with  the  rules 
of  common  arithmetic  through  works  especially 
designed  for  the  purpose. 

RULE.  —  1st,  Separate  the  given  number  into  periods 
of  two  figures  each,  by  placing  a  point  over  the  first 
figure  at  the  right  hand,  and  then  over  every  other 
figure  towards  the  left. 

2d,  Ascertain  the  greatest  square-number  contained 
in  the  left-hand  period,  and  place  the  root  of  it  at  the 
right  hand  of  the  given  number,  after  the  manner  of  a 
quotient  in  division.  Subtract  the  square  of  this  root 
from  the  period  named,  and  to  the  remainder  bring 
down  the  next  period  for  a  new  dividend. 

3d,  Double  the  quotient  already  found,  and  place  it 
at  the  left  of  the  dividend  for  a  divisor.  Find  how 


78  SQUARE-ROOT. 

many  times  this  divisor  is  contained  in  the  new  divi- 
dend (omitting  the  right-hand  figure),  and  place  the 
figure  in  the  root  as  the  second  figure  of  the  same, 
and  likewise  on  the  right  hand  of  the  divisor.  Multi- 
ply the  divisor  by  the  last  quotient-figure,  subtract  the 
product  from  the  dividend,  and  to  the  remainder  bring 
down  the  next  period  for  a  new  dividend. 

4th,  Double  the  quotient  already  found  for  a  partial 
divisor,  and  from  these  find  the  next  figure  in  the  root 
as  before  directed :  so  continue  the  operation  until  all 
the  periods  have  been  employed.  Should  a  remainder 
exist,  add  two  ciphers  as  a  new  period,  and  so  continue 
pointing  off  the  root  after  the  rules  of  decimal  frac- 
tions. 

EXAMPLE.  —  What  is  the^  square-root  of  59,325  ? 

59325  (243.5 
4 

44)193 
176 

483)  1725 

1449 


4865)  27600 
24325 

Required  the  square-root  of  326,041 :  — 

326041(571 
25 


107)  760 
749 

1141)  Till" 
1141 


EQUILIBRIUM 


STRAINS    ON    TIMBER. 


81 


EQUILIBRIUM   OF   STRAINS   ON 
TIMBER. 


A  KNOWLEDGE  of  the  relation  that  one  part  of  a 
frame  sustains  to  each  of  the  others  is  of  great 
importance  to  the  carpenter ;  for,  if  ignorant  of 
the  force  that  each  piece  will  be  required  to  exert 
or  resist,  he  cannot  determine  beforehand  whether 
the  assemblage  will  possess  sufficient  strength  to 
answer  the  purpose  designed.  The  timbers  of  a 
frame  are  usually  acted  upon  by  direct,  and  also 
by  complex,  forces. 


POSITION. 

The  strains  to  which  the  timbers  of  a  structure 
are  subjected  will  always  be  governed  by  their 
position  ;  and  their  particular  inclination  will  in- 
crease or  diminish  these  strains  in  accordance  with 
the  laws  of  mechanical  forces. 

6 


82  EQUILIBRIUM    OP    STRAINS. 


PLATE    H. 

To  the  side  of  a  beam,  as  shown  at  Fig.  1,  Plate  II., 
affix  two  pulleys,  A  and  B.  To  the  ends  of  a  string 
passing  over  each,  attach  weights,  as  C  and  D.  At  some 
point  of  the  string  between  the  pulleys,  as  E,  tie 
another;  to  the  end  of  which  affix  weight  F,  which 
must  be  lighter  than  the  sum  of  the  weights  C  and  D. 

If  the  work  be  then  left  to  itself,  the  point  E  will 
assume  a  certain  position,  and  the  whole  will  remain  at 
rest;  and,  if  the  arrangement  be  disturbed  by  pulling 
down  or  lifting  up  either  of  the  weights,  each  part  will 
recover  its  original  position  when  left  free. 

It  is  thereby  proved,  that,  when  in  that  position  alone, 
the  parts  are  in  equilibria.  If  the  position  of  the 
strings,  when  the  weights  are  thus  balanced,  be  drawn 
on  paper,  and  any  portion  of  the  line  Ei  be  divided  into 
a  scale  of  parts  representing  the  number  of  pounds  in 
the  weight  F,  the  line  AE  be  continued  to  h,  and  the 
line  ik  be  drawn  parallel  to  EB,  then  iTi,  measured 'by 
the  scale,  would  show  the  number  of  pounds  weight  at 
D ;  and  the  line  E^,  measured  in  the  same  manner,  the 
number  of  pounds  in  the  weight  C :  or,  in  other  words, 
the  three  sides  of  the  triangle  'EM  will  be  respectively 
proportionate  to  the  three  weights.  Therefore,  to  ascer- 
tain to  which  weight  either  side  corresponds,  we  have  but 
to  find  which  weight  draws  in  the  direction  of  that  par- 
ticular side. 

As  a  deduction  of  the  foregoing,  we  have  the  follow- 
ing rule :  If  a  body  be  kept  at  rest  by  three  forces,  two 


STRAINS  03f  TDIBEP. 


pi.n 


EQUILIBRIUM    OF    STRAINS.  83 

of  which  are  represented  in  magnitude  and  direction 
by  two  sides  of  a  triangle,  the  third  side  will  represent 
the  magnitude  and  direction  of  the  other  force. 

NOTE.  —  Before  proceeding  to  the  immediate  consideration 
of  the  strains  to  which  timbers  in  a  frame  may  be  subjected, 
the  student  should  make  himself  familiar  with  the  mechanical 
principles  demonstrated  by  Fig.  1,  Plate  II.,  as  the  principles 
therein  contained  are  the  base  on  which  rests  the  science  of 
carpentry. 

We  will  now  suppose  that  the  point  E,  in  Fig.  1,  —  in- 
stead of  being  sustained  by  the  weights  C  and  D,  which 
act  in  the  direction  Ea  and  E6,  as  shown  at  Fig.  2,  —  is 
supported  by  timbers  HE  and  JE.  The  weight  F  being 
suspended  from  the  point  E,  the  timber  HE  will  sustain 
a  force  equal  to  that  which  is  exerted  in  the  direction 
of  E6 ;  and  JE,  a  force  equal  to  that  exerted  in  the  di- 
rection of  Ea. 

To  determine  these  forces,  we  proceed  as  follows :  Let 
any  portion  of  the  line  EF,  as  EG,  represent  the  weight 
F.  Draw  op  parallel  to  HE ;  and  op,  measured  by  the 
scale,  will  represent  the  weight  sustained  by  HE,  and  oq 
that  sustained  by  JE. 

From  the  above  data  we  deduce  the  following :  — 

1st,  A  force  or  power  applied  to  the  end  of  a  timber 
always  acts  in  the  direction  of  its  length. 

Id,  If  a  post  be  somewhat  inclined,  as  AC,  Fig.  3, 
and  another  timber  put  against  it,  as  BC,  the  post  will  be 
relieved  of  a  part  of  the  strain ;  for  each  piece  will  sup- 
port a  weight  proportional  to  its  own  inclination. 

3d,  Should  a  weight  be  applied  to  the  apex  of  two 
pieces  of  like  inclination,  as  at  Fig.  4,  it  will  exert  an 
equal  strain  on  each. 


84  EQUILIBRIUM    OF    STRAINS. 

4th,  A  weight,  applied  as  shown  in  Figs.  3  and  4, 
tends  to  spread  the  timbers  apart  at  the  lower  ends.  In 
Fig.  3,  we  have  supposed  them  to  rest  against  an  im- 
movable abutment.  It  is  obvious,  that,  the  strain  being 
a  direct  thrust,  a  tie  connecting  A  and  B  will  be  an 
equivalent  to  the  abutments.  Fig.  4  represents  this,  AB 
being  the  tie-beam. 

5th,  If  an  inclined  timber,  as  AB,  Fig.  8,  be  cut  at 
the  ends  so  as  to  rest  level  on  the  walls,  it  will  have  no 
tendency  to  slide ;  and  therefore,  so  long  as  it  remains  in 
this  position,  will  not  exert  the  slightest  thrust  on  the 
walls. 


TO   DETERMINE   THE   STRAINS   EXERTED   ON   TIMBER. 

Being  in  possession  of  the  foregoing  facts  and  deduc- 
tions, the  carpenter  is  enabled  to  determine  the  exact 
strain  to  which  the  parts  of  any  piece  of  framing  will  be 
subjected. 

Suppose  it  be  required  to  determine  the  strain  exerted 
on  each  of  the  pieces  shown  at  Fig.  3.  From  the  point 
where  the  pieces  meet,  draw  the  vertical  line  ab  of  any 
convenient  length ;  from  6,  draw  cb  parallel  to  AC.  As- 
suming the  weight  C  to  be  five  hundred  pounds,  we  pro- 
ceed as  follows :  — 

Let  the  line  ab  represent  the  weight.  Divide  it  into 
ten  equal  parts,  and  one  of  these  again  into  ten  others. 
Each  one  of  the  divisions  last  named  —  being  a  hundredth 
part  of  the  line  «6,  which  represents  the  whole  weight 
of  five  hundred  pounds  —  will  represent  five  pounds. 
Measure  the  line  cb  by  this  scale ;  and  as  many  parts  as 
it  contains,  n^iltiplied  by  five,  will  be  the  number  of 


EQUILIBRIUM    OF    STRAINS.  85 

pounds  the  piece  AC  must  support.  Proceed  in  the 
same  way  with  ca,  and  the  result  will  be  the  weight 
supported  by  BC.* 

The  horizontal  strain  exerted  on  the  tie-beam  may  be 
determined  as  follows :  From  the  point  c,  Fig.  4,  draw  a 
line  parallel  to  the  tie-beam.  The  line  cd,  measured  by 
the  scale  as  before  described,  will  represent  the  pressure, 
or  strain,  exerted  thereon  by  each  piece.  If  the  pieces 
be  unequally  inclined,  as  in  Fig.  3,  proceed  as  before 
described ;  and  the  parallel  lines  will  represent  the  hori- 
zontal strain,  as  in  Fig.  4.  af  will  represent  the  vertical 
strain  on  A ;  and  ad,  the  strain  on  B. 

If  a  weight  be  applied  to  any  part  of  an  inclined 
beam,  as  W,  Fig.  8,  the  direct  transverse  strain  may  be 
determined  on  the  same  principles.  From  a  point  be- 
neath the  centre  of  the  weight,  draw  the  line  ab  of  any 
convenient  length.  From  the  end  of  the  line  at  b,  draw 
cb  at  right  angles  with  the  beam.  Having  divided  the 
line  ab  into  a  scale  of  parts  representing  the  number 
of  pounds  weight  at  \V,  we  have,  by  measuring  the  line 
cb  with  this  scale,  the  number  of  pounds  weight  exerted 
as  transverse  or  cross  strain  on  the  beam  AB. 

It  may  also  be  observed,  that  ac  will  give  the  force 
with  which  the  ball  would  move  down  the  beam ;  or,  in 
other  words,  if  the  ball  be  fixed,  it  would  show  the  force 
exerted  in  the  direction  of  the  beam,  dc  will  represent 
the  strain  exerted  on  the  wall,  should  the  beam  rest 
against  it.  Those  strains  to  which  the  several  timbers  of 

*  It  should  be  borne  in  mind,  that  the  particular  inclination 
of  the  pieces  determines  the  aggregate  pressure;  and,  although 
the  sum  of  the  two  may  amount  to  more  than  the  weight  ap- 
plied, it  does  not  necessarily  follow  that  the  calculation  is 
wrong. 


86  EQUILIBRIUM    OF    STRAINS. 

a  crane  are  subjected  are  identical  with  those  exerted  on 
the  various  timbers  of  most  examples  of  framing. 

While  the  crane  is  an  exceedingly  simple  machine,  it 
fully  illustrates  every  point  under  consideration ;  and  has, 
in  consequence,  become  with  most  authors  a  favorite 
model  for  illustration. 

Fig.  5  illustrates  the  nature  and  amount  of  strain  a 
weight  will  exert  on  both  a  tie  and  a  strut  at  the  same 
time.  Instead  of  the  beams  HE  and  JE  of  Fig.  2,  as 
substitutes  for  the  ropes  AE  and  BE  of  Fig.  1,  we  may 
substitute,  in  place  of  rope  EB,  the  strut  CE,  Fig.  5, 
and  permit  a  rope  AE  to  remain.  The  weight  is  sup- 
ported in  this  example  precisely  as  it  was  in  each  of  the 
others,  and  the  method  of  procedure  to  ascertain  the  re- 
spective strains  is  the  same.  EG,  as  a  scale  representing 
the  weight,  is  the  scale  for  measuring  po,  which  is  the 
strain  on  the  strut  CE ;  and  os,  the  strain  on  the  tie,  or 
rope. 

Fig.  6  represents  the  same  principle,  and,  in  like 
manner,  illustrates  the  means  of  determining  the  strain 
on  inclined  timbers.  Ab  represents  the  scale  of  weight. 
The  line  Ac,  measured  by  the  scale,  will  give  the  strain 
on  AB ;  and  be,  that  on  CA.  Should  the  projecting  tim- 
bers be  inclined  downwards,  the  method  of  calculation 
would  be  the  same. 

If  a  beam  be  inclined  against  a  wall,  as  at  Fig.  7,  and 
the  inclination  be  less  than  forty-five  degrees,  there  will 
be  a  tendency  to  slide ;  but  there  is  an  angle  to  which 
the  end  of  the  beam  may  be  cut,  so  that  this  tendency 
will  be  entirely  overcome. 

This  discovery  is  of  great  value  to  the  carpenter,  since 
the  ends  of  truss-rafters,  struts,  &c.,  formed  in  accord- 
ance with  the  rule,  will  exert  no  lateral  strain  on  the 
wood  against  ^which  it  abuts. 


EQUILIBRIUM    OF    STRAINS.  87 

From  the  centre  of  the  beam  at  d,  draw  the  line  ab 
parallel  to  AC.  From  a,  draw  of  to  the  centre  of  the 
beam  at  f;  then,  from  a,  draw  ag  to  the  centre  of  the 
inclined  beam  at  the  lower  end.  ag  will  represent 
the  direction  in  which  the  beam  presses  upon  the  abut- 
ment at  B  or  g ;  and  the  parts  should  therefore  be  cut 
at  right  angles  to  the  line  named. 

If  we  divide  the  line  ab  into  a  scale  representing  the 
weight  on  the  centre  of  the  beam,  and  draw  be  perpen- 
dicular thereto,  be  will  represent  the  pressure  against  the 
abutment,  or  the  tensile  strain  exerted  on  the  beam  AB. 

The  foregoing  comprehends  all  the  important 
principles  relative  to  the  strains  exerted  on  the 
timbers  of  a  frame.  In  calculating  these,  however, 
it  is  to  be  remembered,  that  the  simpler  a  piece 
of  framing  is,  so  is  the  resolution  of  the  forces 
exerted  upon  it;  and  vice  versa.  Although,  in 
most  instances,  strains  are  more  or  less  complicated, 
interfering  with,  and  at  times  counteracting,  each 
other,  still  the  exact  strain  upon  each  part  is  sus- 
ceptible of  calculation ;  and  any  one  who  has  suffi- 
cient curiosity  and  perseverance  may,  by  following 
the  rules,  determine  the  nature  and  quantity  of 
the  strain  exerted  on  any  specimen  of  framing, 
however  complicated. 


SCARFING,    FLOORS,    AND 
TRUSSED  BEAMS. 


91 


SCARFING. 


IT  frequently  occurs  in  the  practice  of  carpentry, 
that  single  lengths  of  timber  are  too  short  for  the 
distance  required;  in  which  case,  the  carpenter 
unites  two  or  more  pieces  by  a  process  technically 
termed  SCARFING.  The  principal  end  to  be  at- 
tained is,  that,  when  put  together,  the  scarfed  stick 
shall  be  equal  in  strength  to  a  single  piece  of  the 
same  dimensions.  To  attain  this,  it  is  necessary 
so  nicely  to  adjust  the  indentations,  that  the  entire 
surface  of  each  part  shall  come  in  contact  with 
the  corresponding  part  in  the  other  piece ;  so  that 
all  may  have  a  direct  and  uniform  bearing,  and 
none  be  made  to  resist  a  force  that  should  be 
resisted  by  another. 

Methods  of  scarfing  are  various ;  and,  of  many, 
we  may  truly  say,  that  their  design  savors  more  of 
the  imagination  of  the  artist  than  the  sober  expe- 
rience of  the  mechanic. 


92  SCARFING. 

As  it  is  not  the  purpose  of  this  work  to  illustrate 
the  whole  range  of  experiments  in  these  things, 
such  methods  only  will  be  given  as  have  proved 
themselves  most  useful,  presuming  these  will  meet 
every  reasonable  demand ;  remarking  merely,  that, 
when  more  complicated  forms  of  indentation  are 
made,  it  is  always  at  the  expense  of  utility. 

Beams  are  seldom  exposed  to  more  than  two 
kinds  of  strain  which  act  upon  the  scarfing.  One 
is,  when  the  power  is  so  applied  as  to  exert  a  strain 
in  the  direction  of  the  beam's  length,  as  that  pro- 
duced by  truss-rafters  on  a  tie-beam :  the  other  is, 
when  the  force  or  power  tends  to  sag  or  break  the 
beam  in  the  direction  of  its  depth. 

In  consideration  of  which,  attention  should  be 
paid,  in  the  selection  of  a  method  of  scarfing,  to  the 
particular  kind  of  strain  to  which  the  beam  is  most 
liable  to  be  subjected. 

The  parts  of  a  piece  of  scarfing  are  held  together 
by  bolts  passing  through  the  stick,  as  shown  in 
the  plate ;  and  oak-keys  are  frequently  put  into  the 
scarf  to  prevent  the  parts  sliding  past  each  other, 
as  seen  at  a.  Figs.  1,  2,  3.  Care  should  be  taken 
that  neither  bolts  nor  keys  be  so  large  as  to  require 
the  removal  of  such  an  amount  of  wood  as  will 
materially  weaken  the  timber. 


SCARFING.  93 

These  keys  should  be  made  of  perfectly  sound 
dry  white  oak.  They  should  be  in  two  parts,  each 
slightly  tapering  on  one  side,  so  that,  when  driven 
in,  they  may  tighten  the  joint. 

The  iron  straps  or  bars  used  on  a  scarf  (as 
shown  on  some  of  the  examples)  should  be  of  the 
best  wrought  iron,  from  a  fourth  to  a  half  inch  in 
thickness,  and  from  two  to  three  inches  wide,  ac- 
cording to  the  size  of  the  beam  scarfed ;  and  should 
be  four  in  number  to  each  scarf.  The  length  of  the 
scarfing  for  any  beam  should  be  about  six  times  the 
depth  of  the  stick,  and  the  bolts  which  confine 
the  work  together  should  be  from  a  half  to  three- 
fourths  of  an  inch  in  diameter ;  making  five-eighths 
of  an  inch  as  the  best  average  size  for  bolts  to 
beams  of  any  dimension  above  eight  or  nine  inches 
square. 


94  SCARFING. 


PLATE    III. 

Plate  III.  exhibits  five  specimens,  or  examples,  of  scarf- 
ing. Figs.  1,  3,  and  5  are  best  adapted  to  resist  a  strain 
in  the  direction  of  the  length  of  the  beam ;  and  Figs.  1, 
2,  and  4,  to  resist  one  in  the  direction  of  its  depth.  In 
Figs.  4  and  5,  the  pieces  are  too  short  to  admit  of  either 
of  the  other  methods.  The  planks  of  example  at  Fig.  5 
should  be  of  good  dry  white  oak ;  and,  if  the  work  is  well 
done,  this  scarf  is  equal  in  strength  to  either  of  the  more 
complicated  methods.  This  practice  is  called  by  carpen- 
ters "fishing  a  beam." 

It  is  well  to  observe  here,  that  the  examples  cited  as 
being  particularly  adapted  to  resist  a  longitudinal  strain 
are  also  capable  of  sufficiently  resisting  a  vertical  one. 


SCARFING 


Pl.Ul 


i      i  T    r      i 


i      i 

"T^-il 

-^ 4- 


I  i  ! 

I  I 


Tig.  5. 


T T 


95 


FLOORS. 


THE  construction  of  floors  is  a  branch  of  carpentry 
which  does  not  demand  much  scientific  considera- 
tion. If  the  timber  be  of  proper  size,  sufficient  in 
quantity,  and  the  work  well  done,  all  is  accom- 
plished that  can  be  desired.  To  effect  this,  how- 
ever, the  carpenter  should  avail  himself  of  such 
rules  as  experience  has  proved  to  be  valuable.  The 
timbers  of  a  floor  should  be  selected  of  proper  size 
to  support  any  weight  that  will  probably  be  placed 
upon  them.  A  warehouse-floor,  for  instance,  may 
at  times  be  subjected  to  great  strains,  and  should 
therefore  be  heavily  timbered.  It  is  often  the 
practice,  in  constructing  floors  of  the  kind,  to  use 
long  floor-joists  extending  from  eighteen  to  twenty- 
four  feet;  in  which  case,  the  timbers  vary  in  di- 
mensions from  three  by  thirteen  inches  to  five  by 
fourteen  inches,  and  they  are  usually  placed  from 
fifteen  to  twenty  inches  apart  from  centres.  A 


96  FLOORS. 

church  or  hall  floor,  when  covered  with  people  in 
a  standing  position,  packed  close,  is  loaded  a  hun- 
dred and  twenty-five  pounds  to  each  square  foot. 
Timbers  three  by  twelve  inches,  if  the  bearings  are 
not  more  than  ten  feet  apart,  placed  sixteen  inches 
from  centres,  will  sustain  the  weight;  and  these 
dimensions  are  generally  used  in  buildings  of  the 
kind. 

The  floors  of  dwelling-houses  may  be  lighter. 
If  the  joists  are  materially  longer,  the  size  should 
not  be  much  decreased.  The  lengths  being  from 
nine  to  fifteen  feet,  two  by  twelve  will  answer  the 
purpose :  two  by  ten  inch  joists,  and  even  two  by 
eight  inch,  are  frequently  used  in  cheap  buildings. 
The  principal  objection  to  light  timber  arises,  not 
from  its  liability  to  break,  but  from  its  vibration, 
which  is  apt  to  crack  the  plaster  of  the  ceiling 
below. 


FLOORS 


n.r 


.._ 


Ffe.4. 


:  -,  :  '  .     . 


Cmith .  Knight  *  Tappan.Eng' 


FLOORS.  07 


PLATE    IV. 

The  method  of  framing  shown  at  Fig.  1  of  this  plate, 
is,  all  things  considered,  quite  as  good  as  any  in  use. 
More  complicated  methods  are  not  often  attended  with 
proportionate  advantage.  Fig.  2  exhibits  the  side  of 
the  joists  of  the  same  floor,  the  girder,  &c.,  all  of  which 
will  be  readily  understood  without  further  explanation. 

Fig.  3  exhibits  a  section  of  what  is  called  a  bridged 
floor.  It  is,  in  principle,  like  the  other,  with  the  addi- 
tion of  the  smaller  joists  which  bridge  over  the  principal 
ones.  Floors  of  this  kind  are  seldom  built  in  this  coun- 
try, but  are  much  used  in  Europe. 
,  Fig.  4  exhibits  a  side-view,  or  section,  of  the  floor 
last  described ;  BB  showing  the  ends  of  the  principal, 
and  C  the  side  of  the  bridging,  joists.  The  part  of 
the  diagrams  at  A  illustrates  the  method  of  framing  the 
joists  into  the  girder;  the  figures  thereon  denoting 
the  dimensions  of  each  part,  being  calculated  for  a  stick 
twelve  inches  deep. 

Even-  floor  should  be  well  bridged.  This  may  be 
done  in  either  of  two  ways :  first,  by  cutting  in  between 
the  sides  of  the  joists,  and  at  right  angles  to  them, 
pieces  of  the  same  thickness  and  width  as  the  joists 
themselves;  secondly,  by  cutting  in  pieces  of  board  one 
inch  thick  and  three  inches  wide,  crossing  each  other  dia- 
gonally, as  seen  at  a,  Fig.  1,  Plate  IV.  The  ends  of 
these  pieces  are  scarfed,  or  cut  bevelling,  and  firmly 
nailed  to  the  sides  of  the  joists. 


98 


TRUSSED     BEAMS. 


IT  frequently  happens  that  beams  are  required  to 
support  a  great  weight,  while  they  extend  across 
a  wide  space,  and  can  have  no  support  from  be- 
neath. In  such  cases,  it  is  necessary  to  truss  the 
work. 


PLATE    V. 

Fig.  1,  Plate  V.,  exhibits  a  method  of  trussing  a  beam 
by  the  use  of  an  iron  rod.  All  trussed  beams  are  com- 
posed of  two  pieces.  In  the  example  at  Fig.  1,  the 
pieces  are  placed  an  inch  apart,  and  the  rod  so  bent  as  to 
take  the  sag  of  the  beam  at  the  points  aa.  A  bolt,  an 
inch  in  diameter,  passes  through  the  beam,  and  rests 
on  the  truss-rod.  At  bb  are  iron  plates,  through  which 
the  ends  of  the  rod  pass.  This  method  may  be  employed 
where  the  span  is  from  twenty-five  to  thirty-five  feet.  If 
the  work  is  well  done,  the  girder  is  strong ;  but  the  ex- 
pansion and  contraction  of  the  rod  subject  the  work  to 
variation  as  the  rod  becomes  longer  or  shorter. 


-  Ls 


i-Eiagfet  &  Tampan.  EngT? 


TRUSSED    BEAMS.  99 

Figs.  3  and  4  are  examples  where  oak-pieces  and  cast- 
iron  keys  are  used  instead  of  a  rod.  The  oak-parts 
should  be  two  by  four  inches,  and  let  into  the  wood  a 
quarter  of  an  inch  on  each  side,  leaving  the  beams  an  inch 
and  a  half  apart.  The  keys  should  be  made  with  a 
screw  and  nut  at  c  to  tighten  the  work.  The  abutments 
at  dd  should  also  be  of  cast  iron,  and  let  into  the  wood, 
like  the  oak. 

Fig.  2  represents  a  beam  built  with  oak-keys,  two 
inches  square,  let  half  an  inch  into  the  pieces,  and  the 
whole  bolted  together.  This  method  produces  a  very 
strong  beam,  and  is  of  great  value.  It  is  often  the  prac- 
tice in  carpentry  to  bolt  two  pieces  of  spruce  together, 
with  an  oak-board  an  inch  thick  between  them.  The 
bolts  should  be  of  wrought  iron,  and  five-eighths  of  an 
inch  in  diameter.  Should  unusual  strength  be  required, 
the  beam  may  be  built  with  three  or  even  four  pieces, 
with  the  truss-work  between  them,  and  the  whole  bolted 
together  as  in  an  ordinary  beam. 


ROOFS,  PARTITIONS,  AND  DOMES. 


103 


E  0  O  F  S. 


tt  THERE  is  no  article,"  says  the  learned  Ware,  "  in 
the  whole  compass  of  the  architect's  employment, 
that  is  more  important,  or  more  worthy  of  distinct 
consideration,  than  the  roof;  and  there  is  this  satis- 
faction for  the  mind  of  the  man  of  genius  in  that 
profession,  that  there  is  no  part  in  which  is  greater 
room  for  improvement." 

The  suggestions  above  quoted,  although  made 
in  the  year  1756,  remained  quite  unheeded  till 
near  the  close  of  the  last  century,  when  Mr.  Peter 
Nicholson  made  public  the  germ  of  an  invention, 
which  has,  in  process  of  time,  brought  about  as  great 
a  revolution  in  the  art  of  carpentry  as  the  introduc- 
tion of  the  arch  did  in  that  of  masonry.  The  lead- 
ing feature  of  the  invention  is  the  substitution  of 
iron  rods  for  wooden  king  and  queen  posts.  The 
design  by  Mr.  Nicholson  was  published  in  1797; 
but,  as  late  as  1828,  Mr.  Tredgold  says,  in  his  ex- 


104  ROOFS. 

cellent  Treatise  on  Carpentry,  "  It  has  been  proposed 
to  let  the  ends  of  the  principal  rafters  abut  against 
each  other,  and  to  suspend  the  king-posts  by  straps 
of  iron ;  but  a  piece  of  good  carpentry  should  de- 
pend as  little  on  straps  as  possible."  From  the  tenor 
of  his  remarks,  it  is  reasonable  to  suppose  that  few, 
if  any,  successful  experiments  had  been  made ;  for 
he  afterwards  refers  the  reader  to  a  design  in  his 
work,  where  the  rafters  abut  against  each  other, 
and  the  beam  is  suspended  by  planks  bolted  to  their 
sides.  "This  method,"  he  adds,  "is  perhaps  the 
best  in  use."  A  valuable  standard  work,  entitled 
"  Treatise  on  Architecture,  Building,  &c.,"  was  pub- 
lished in  Edinburgh  in  1844.  On  page  154  of 
the  work,  attention  is  called  to  the  suggestion  of  Mr. 
Nicholson,  made  forty-seven  years  before.  The 
writer  (Dr.  Thomas  Young)  says,  "  There  is  a  very 
ingenious  project  offered  to  the  public  by  Mr. 
Nicholson  ('  Carpenter's  Assistant,'  p.  68).  He 
proposes  iron  rods  for  king-posts,  queen-posts,  and 
all  other  situations  where  beams  perform  the  office 
of  ties.  .  .  .  "We  abound  in  iron  ;  but  we  must 
send  abroad  for  building-timber.  This  is,  therefore, 
a  valuable  project.  At  the  same  time,  however,  let 
us  not  overrate  its  value."  From  the  foregoing,  it 
appears,  that,  up  to  a  late  day,  but  little  advance  had 


ROOFS.  105 

been  made ;  the  old  methods  of  construction  being 
looked  upon  with  more  favor  than  the  new. 

At  what  time,  or  by  whom,  the  idea  was  first 
practically  carried  out  in  this  country,  is  uncertain. 
The  burden  of  evidence,  however,  indicates,  that, 
although  first  published  by  Mr.  Asher  Benjamin, 
he  was  indebted  for  the  suggestion  to  Mr.  Charles 
G.  Hall,  now  of  Roxbury,  Mass.  Mr.  Hall,  an 
Englishman  by  birth,  and  an  able  architect  and 
engineer,  arrived  in  America  in  1823.  He  soon  be- 
came associated  in  business  with  an  eminent  archi- 
tect of  that  day,  Mr.  Alexander  Parris.  Under  the 
direction  of  these  gentlemen,  many  large  and  im- 
portant buildings  were  erected,  in  the  roofs  of  most, 
if  not  all,  of  which,  the  principle  under  considera- 
tion was  employed.  Being  thus  freely  used,  it  soon 
commended  itself  to  the  judgment  of  other  archi- 
tects, who  in  turn  adopted  it ;  and  the  work  of  Mr. 
Benjamin  was  no  sooner  published  than  a  reform 
commenced,  which  has  steadily  advanced,  until  its 
great  value  and  economy  are  universally  acknow- 
ledged. 

On  the  plates  of  this  work  pertaining  to  roofs 
are  designs  calculated  for  various  spans,  and  of  such 
rise,  or  pitch,  as  will  accommodate  them  to  any  style 
of  building;  each  having  been  so  designed  that 


106  ROOFS. 

timber  may  be  used  of  such  dimensions  as  will 
properly  support  a  covering  of  heavy  slates. 

Of  the  inclination,  or  pitch,  of  the  several  roofs, 
but  little  need  be  said,  since  designs  for  buildings 
are  so  varied,  that  an  attempt  to  illustrate  them  all 
would- only  encumber  the  work.  A  few  suggestions 
will  be  made,  which,  together  with  those  amendments 
naturally  presenting  themselves  in  particular  cases, 
will  give  all  the  information  required. 

The  pitch  of  any  roof,  covered  with  shingles  or 
slates,  should  never  be  less  than  one-fourth  the 
width  of  the  entire  span ;  for,  if  it  be  less,  rain  and 
snow  will,  in  severe  storms,  be  driven  through  the 
crevices.  If  the  design  of  the  building  demands 
less  inclination,  a  covering  of  tin,  copper,  lead,  or 
something  of  like  nature,  should  be  used ;  in  which 
case,  any  rise  above  a  twenty-fourth  of  the  whole 
span  will  be  all  that  is  required.  The  extent  of 
the  span  will,  however,  to  a  certain  degree,  govern 
the  inclination  and  form  of  the  roof,  in  order  to 
give  strength  to  the  truss.  If  the  span  is  great, 
and  a  low  roof  is  desired,  it  is  best  to  truncate  it, 
as  shown  on  Plate  IX.,  Fig.  1.  Where  slating  is 
used,  the  boards  should  be  matched,  and  planed  to  a 
uniform  thickness ;  for  if  the  joints  are  left  open, 
as  may  be  allowed  in  shingling,  the  passage  of  air 


ROOFS.  107 

through  the  openings  carries  with  it  rain  or  dry 
snow,  when,  in  ordinary  storms,  it  would  exhibit  no 
sign  of  defect. 


TIMBERS    OF  A  ROOF. 

A  trussed  roof  employs  the  following  timbers,  — 
tie-beams,  principal  rafters,  collar-beams,  struts, 
purlines,  and  common  rafters. 

TIE-BEAMS  are  the  large  and  long  timbers  which 
lie  in  a  horizontal  position,  and  extend  across  the 
building  at  the  base  of  the  roof.  They  are  usually 
subjected  to  two  kinds  of  strain.  One  is  that  which 
is  exerted  by  the  principal  rafters :  the  other  is  the 
cross-strain,  and  may  be  produced  by  the  weight 
of  the  ceiling  below,  or  a  load  upon  the  beams 
themselves.  In  mortising  tie-beams,  as  little  wood 
should  be  removed  as  the  nature  of  the  case  will 
allow.  Tenons  may  be  small,  their  use  being  simply 
to  retain  each  piece  in  its  proper  place.  If  the 
figuring  laid  down  in  this  work  is  followed,  the  tie- 
beams  of  each  design  will  be  of  sufficient  size  to 
resist  the  strains  exerted  by  the  inclined  parts,  and 
the  rods  will  resist  the  cross-strain. 

The  weakest  part  of  a  tie-beam,  and  hence  the 


108  ROOFS. 

one  demanding  most  attention,  is  at  its  ends  about 
the  foot  of  the  rafters.  To  strengthen  this  part,  it 
is  the  usual  practice  to  bolt  pieces  of  strong  white 
oak  or  Carolina  pine  to  the  under  side  of  the 
beam.  The  pieces  should  be  as  thick  as  half 
the  depth  of  the  beam,  and  of  sufficient  length  to 
extend  from  the  end  thereof  to  three  feet  beyond 
the  heel  of  the  rafters.  (See  S,  Fig.  2,  Plate  VI.) 
Objections  to  the  use  of  strengthening-pieces  have 
been  made,  because  they  present  a  joint  or  seam 
where  dampness  may  gather,  and  produce  decay  in 
the  wood ;  also  because  they  are  in  effect  a  camber 
to  the  beam,  exerting  a  thrust  on  the  walls  of  the 
building.  To  a  certain  extent,  these  objections  are 
valid ;  but  neither  is  of  sufficient  moment  to  out- 
weigh the  benefit  produced.  The  objection  first 
named  may  be  entirely  obviated  by  thoroughly 
painting  the  pieces  when  the  work  is  put  together. 
The  practice  of  cambering  a  tie-beam,  by  tightening 
the  rods  till  the  beam  is  curved  upwards,  cannot  be 
considered  advisable;  for,  if  sufficient  camber  is 
produced  to  give  the  beam  additional  strength  by 
its  partaking  of  the  nature  of  an  arch,  this  is  more 
than  counteracted  by  injury  to  the  walls  of  the  build- 
ing. A  large  ceiling,  if  entirely  level,  presents  an 
optical  delusion,  leading  the  beholder  to  believe 


ROOFS.  109 

that  the  surface  has  a  sag,  or  downward  curve.  In 
furring  such  ceilings,  a  rise  of  an  inch  in  twenty 
feet  will  obviate  the  difficulty.  While  the  carpenter 
is  cautious  in  cambering  beams  for  either  of  the 
purposes  named,  or  any  of  like  nature,  he  should 
remember  that  there  will  be  a  settlement  from  the 
shrinkage  of  the  timbers,  till  each  part  has  found 
a  solid  bearing.  Hence  the  rods  should  be  kept 
tightened ;  and,  when  the  work  is  completed,  the 
centre  of  the  beam  should  be  slightly  curved  upwards, 
that  the  tendency  named  may  be  counteracted. 

PRINCIPAL  RAFTERS  are  the  large  inclined 
timbers  which  support  the  purlins :  they  should 
be  of  the  same  thickness  as  the  tie-beam,  and  about 
four-fifths  as  deep.  To  a  beam  seven  by  ten  inches, 
the  rafter  would  be  seven  by  eight  inches.  In  some 
examples  of  framing,  as  that  shown  on  Plate  XL, 
Fig.  1 ,  one  rafter  is  placed  above  another ;  in  which 
case,  both  should  be  of  the  same  size,  having  pieces 
of  oak-board,  an  inch  and  five-eighths  thick  and 
four  inches  wide,  let  into  each  rafter  five-eighths  of 
an  inch,  leaving  the  rafters  three-eighths  of  an  inch 
apart  for  the  passage  of  air  between  them :  the  pieces 
should  be  perfectly  dry,  and  tightly  driven  into  the 
grooves.  The  timbers  should  be  bolted  together 
with  bolts  five-eighths  of  an  inch  in  diameter. 


110  ROOFS. 

COLLAR-BEAMS  are  the  horizontal  timbers  which 
lie  between  the  heads  of  principal  rafters.  They  are 
also  known  as  straining-beams.  As  their  use  is 
to  prevent  the  rafters  approaching  each  other,  their 
dimensions  may  be  the  same  as  the  timbers  named. 
In  designs  where  these  beams  are  liable  to  sag,  they 
should  be  supported  with  struts,  as  seen  at  A,  Plate 
VIII.  The  case  not  unfrequently  occurs  where  col- 
lar-beams are  serviceable  as  tie-beams,  and  thereby 
strengthen  the  principal  tie-beam :  an  example  of 
this  kind  may  be  seen  at  B  and  C,  Plate  XI.  In 
cases  of  this  kind,  separate  rods  will  be  required. 
The  top-truss,  being  needed  as  a  truss,  will  require 
rods  of  its  own  to  make  it  complete  in  itself;  the 
main-beam  being  suspended  by  other  rods. 

STRUTS  are  the  inclined  pieces  which  support  the 
principal  rafters.  The  ends  of  struts  should  always 
be  framed  with  a  shoulder  an  inch  and  a  half  wide, 
and  sloping  from  this  to  the  end  of  the  piece.  It 
may  be  remarked  here,  that  the  ends  of  all  braces 
(whatever  their  position)  should  be  formed  with  a 
shoulder  of  like  nature,  proportional  to  the  size  of 
the  piece.  Struts,  being  always  in  a  state  of  com- 
pression, need  not  be  pinned  to  the  beam  or  piece 
they  support,  a  short  tenon  being  all  that  is  required 
to  keep  the  parts  in  their  proper  place.  The  width 


ROOFS.  Ill 

of  struts  should  be  the  thickness  of  the  principal  raf- 
ter ;  and  they  should  be  about  half  as  thick  as  the 
rafter  is  deep.  The  carpenter  should  make  it  an 
invariable  rule  to  place  the  curved  or  cambered 
side  of  a  timber  upwards,  whenever  such  cambered 
side  exists. 

PURLINS  are  the  horizontal  timbers  extending 
from  truss  to  truss  to  support  the  common  rafters. 
They  should  always  be  framed  or  bridged  over  the 
principal  rafters,  by  notching  into  the  back  of 
them  and  breast  of  the  purlins,  each  half  an  inch, 
making  an  inch  when  the  work  has  been  put  to- 
gether. Their  size  is  determined  by  their  length 
of  bearing  and  distance  apart.  "When  the  trusses 
are  within  ten  feet  from  centres,  and  the  purlins 
less  than  eight  feet  apart  on  the  principal  rafters, 
they  may  be  ,to  them  in  thickness  and  depth, 
respectively,  as  five  to  eight.  They  should  not 
be  cut  into  lengths  which  will  reach  only  over 
single  spaces,  but  continued  whole ;  and,  when 
they  are  put  on,  they  should  be  made  to  break 
joints,  by  the  use  of  short  lengths  at  the  end  of 
every  other  one.  It  is  to  be  remembered,  that  the 
joints  should  always  be  made  over  the  principal 
rafter.  In  cases  where  the  roof  is  large,  and  ex- 
posed to  the  direct  action  of  heavy  storms,  the 


112  ROOFS. 

purlins  should  be  braced,  like  the  posts  and  girts 
of  a  side-wall. 

COMMON  RAFTERS  are  the  outside  timbers  of  a 
roof,  and  are  used  simply  to  support  the  boarding. 
Being  uniformly  loaded,  only  light  pieces  are  re- 
quired ;  but  they  should  always  be  jointed  over  the 
purlins,  and  never  placed  more  than  eighteen  or 
twenty  inches  apart  from  centres.  If  the  bearing 
is  not  more  than  eight  feet,  they  may  be  two  by 
six  inches ;  but,  where  it  is  more,  their  depth 
should  be  proportionally  increased.  They  should 
be  notched  into  a  half-inch,  to  keep  them  from 
sliding  off  the  purlin ;  but  the  purlin  itself  should 
remain  entire. 


IRON    WORK. 

The  bolts  used  at  the  foot  of  principal  rafters 
should  not  be  less  than  five-eighths  of  an  inch  in 
diameter,  nor  more  than  an  inch.  For  most  pur- 
poses, three-fourths  of  an  inch  is  best ;  and,  when 
one  of  an  inch  in  diameter  is  not  sufficiently  strong, 
it  is  better  to  increase  the  number  than  the  size, 
and  they  should  always  be  set  at  right  angles  with 
the  rafters.  The  rods  which  support  the  beams 


ROOFS.  113 

must  be  of  sufficient  size  to  prevent  vibration,  but 
may  vary  in  diameter  according  to  the  nature  of 
the  work,  from  five-eighths  of  an  inch  to  two  inches 
in  diameter. 

Great  cafe  should  be  exercised  in  the  selection, 
using  none  but  the  very  best  material. 

It  is  a  common  practice,  in  some  instances,  to  use 
cast-iron  boxings  at  the  ends  of  principal  rafters, 
and  such  other  parts  of  a  truss  as  will  be  subjected 
to  great  pressure,  causing  the  fibres  of  the  wood  to 
indent  each  other.  It  is  rare,  however,  that  box- 
ings are  absolutely  necessary. 

Where  a  piece  of  framing  is  liable  to  be  exposed 
to  dampness  before  the  work  is  put  together,  the 
iron  should  be  heated  to  a  blue  heat,  and  well  oiled 
over  with  the  best  quality  of  raw  linseed  oil.  If 
this  is  properly  done,  the  pores  of  the  iron  will  be 
filled,  and  the  metal  effectually  protected  against 
corrosion. 

Straps  should  be  used  sparingly,  if  at  all ;  as  the 
shrinkage  of  the  wood  leaves  them  loose,  and 
the  work  is  liable  to  settle.  In  most  examples  of 
old  carpentry,  these  were  freely  used ;  but  modern 
methods  of  framing  with  rods  and  bolts  have  ob- 
viated the  necessity  for  them,  so  that  they  are  now 
but  rarely  employed. 


114 


ROOFS. 


PLATE    VI. 

Fig.  3  of  this  plate  exhibits  a  design  for  a  roof  of 
from  forty  to  sixty  feet  span.  Being  very  simple  in  its 
construction,  it  is  more  frequently  used  than  any  other. 
The  trusses  should  be  not  more  than  eight  or  ten  feet 
apart,  and  the  common  rafters  twenty  inches  apart,  from 
centres. 


Table  of  dimen 


in  inches,  of  limbers  for  roofs  of  various 
spans. 


NAMES. 

Span  in  Feet. 

40 

45 

50 

55 

60 

Tie-beams    .... 
Truss-rafters     .    .    . 
Collar-beams    .    .    . 
Common  Eafters  .    . 

6x8 
6x7 
6x7 
2x6 
5x7 
3x6 
4x6 
lin. 
iin. 

7x8 
7x7 
7x7 
2x6 
6x7 
4x7 
5x7 
Uin. 
|in. 

8x9 
8x8 
8x8 
2x6 
6x8 
4x8 
5x8 
Uin. 
fin. 

8x10 
8x9 
8x9 
2x7 
6x8 
5x8 
5x8 
Uin. 
lin. 

9x11 
9x9 
9x9 
2x7 
6x9 
5x9 
6x9 
Uin. 
Uin. 

Struts 

Strengthening-pieces 
Rods    
Bolts  .  '  

Fig.  1  exhibits  in  detail  the  framing  at  A,  and  Fig.  2 
that  at  B. 


Pl.TE 

' ~| 


pp« 


LOOFS 


ROOFS. 


115 


PLATE    VH. 

Fig.  2  exhibits  a  design  for  a  roof  of  from  thirty- 
five  to  fifty  feet  span.  This  roof,  from  its  simplicity  and 
strength,  is,  like  that  on  Plate  VL,  much  approved, 
and  in  common  use. 

Table  of  timber-dimensions  for  various  spans. 


Span  i 

i  Feet. 

35 

40 

45 

50 

Tie-beams      .... 

6X7 

6x8 

7X9 

8x9 

Truss-rafters       .     . 

6X6 

6x7 

7X8 

8x8 

Common  Rafters     .... 
Struts                       .    . 

2X6 
2x6 

2X6 
3X6 

2X6 
3X6 

2X6 
4X6 

Purlins 

4X7 

5X7 

6X7 

6X8 

Rod 

r  jn 

1  in 

li  in. 

Hin. 

Bolt 

1  ! 

4  in 

3  in 

i  in 

1  in 

Fig.  1  exhibits  an  example  of  a  roof,  with  tie-beams, 
so  framed  as  to  admit  of  finishing  a  curved  ceiling.  The 
practice  of  thus  dispensing  with  a  horizontal  or  single 
tie-beam  should  be  used  with  great  caution,  as  the  work 
is  always  liable  to  settle. 

Table  of  limber-dimensions  for  various  spans. 


NAMES. 

Span  in  Feet. 

40 

45 

50 

Tie-beams    

6X8 
6X7 
2X6 
2X6 
5X7 
4X6 
1  in. 
fin. 

6X9 

6X8 
2X6 
3X6 
6X7 
5X6 
l|in. 
iin. 

6X10 
6X9 
2X6 
4X6 
6X8 
6X6 
Uin. 
1  in. 

Truss-rafters     

Common  Rafters  

Struts      

'.   Purlins    

Rods    

Bolts   

116 


HOOFS. 


PLATE    VHI. 

Fig.  3  exhibits  a  design  for  a  roof,  with  inclined  tie- 
beams,*  and,  having  been  executed  many  times  with 
perfect  success,  may  be  considered  as  entirely  reliable 
for  any  span  of  less  than  seventy-five  feet.  The  tie-beams 
are  halved  together;  and  the  planks  at  the  intersection 
should  be  of  dry  white  oak  or  chestnut,  bolted  to  the 
beams  with  bolts  five-eighths  of  an  inch  in  diameter.  The 
centre  rod  should  be  made  forked  at  the  lower  end,  one 
part  passing  down  outside  of  each  plank,  with  an  eye  on 
each  tine,  through  which  passes  a  bolt,  crossing  the  beams, 
and  supporting  them  at  the  intersection.  It  is  apparent, 
that,  so  long  as  the  distance  from  C  to  D  remains  the 
same,  no  settling  can  take  place,  or  thrust  be  exerted  on 
the  side-walls. 

Table  of  timber-dimensions  for  various  spans. 


Span  in  Feet. 

NAMES 

40 

45 

50 

55 

60 

65 

70 

Tie-beam 

6X8 

6X9 

7X10 

7X11 

8X10 

8X11 

9X12 

Truss-  rafter 

6X7 

6X8 

7X9 

7X10 

8X9 

8X10 

9X10 

Com.  Rafter 

2X6 

2X6 

2X6 

2X7 

2X7 

2X8 

2X8 

Collar-beam 

6X7 

6X8 

7X9 

7X10 

8X9 

8X10 

9X10 

Purlins     . 

5X7 

5X8 

6X8 

6X8 

6X8 

6X9 

7X9 

Struts  .     . 

3X6 

3X6 

3X7 

4X7 

4X8 

6X8 

5X9 

Long  Rods 

lin. 

l*in. 

1|  in. 

1|  in. 

l£in. 

If  in. 

l|in. 

Short     „ 

Jin. 

lin. 

lin. 

lin. 

If  in. 

l]  in.     14  in. 

Bolts   .     . 

fin. 

fin. 

Jin. 

fin. 

lin. 

1£  in. 

IJln. 

*  This  roof  was  executed  first  at  the  Unitarian  church  of 
Sornerville,  Mass.,  in  the  year  1850,  from  drawings  furnished 
by  the  author;  the  leading  idea  having  been  suggested  by  Rev. 
Augustus  R.  Pope,  minister  of  the  society.  A  very  heavily 
stuccoed  ceiling  is  appended  to  it,  but,  after  a  test  of  six 
years,  is  as  perfect  as  when  first  built. 


PI. IX 


HOOFS 


ROOFS.  117 


PLATE    IX. 

Fig.  1,  on  Plate  IX.,  is  a  design  for  a  low  roof  of  wide 
span.  The  figures  show  the  dimensions  of  timber  for  one 
of  from  sixty-five  to  seventy-five  feet.  It  may  be  ex- 
tended to  ninety  feet  by  a  proportional  increase  in  the 
size  of  the  rods  and  timbers. 

Fig.  2  shows  a  roof  of  from  eighty  to  a  hundred  and 
twenty  feet  span.  The  figures  on  the  engraving  are  cal- 
culated for  one  of  a  hundred  feet,  and  should  be  increased 
or  diminished  according  to  its  width. 

The  tie-beam  in  this  design  should  be  made  of  two 
four-by-fourteen-inch  planks,  with  short  pieces  of  two-inch 
planks  at  intervals  between  them. 

Some  of  the  bearings  in  each  of  these  examples  are 
designed  to  be  of  cast  iron,  as  will  be  discovered  by  con- 
sulting the  drawing. 


118  ROOFS. 


PLATE    X. 

Plate  X.  exhibits  two  designs  for  curved  roofs.  The 
tie-beams  of  each  are  in  two  pieces,  with  a  two-inch  plank 
between  them;  and  the  struts,  where  they  cross,  are 
notched  into  each  other,  so  that  their  sides  may  be  flush 
with  those  of  the  beams. 

Fig.  1  represents  a  segmental  roof.  The  figures  denote 
the  size  of  timber  for  a  span  of  seventy-five  feet.  If  the 
span  be  increased  to  ninety  feet,  the  size  of  the  timber 
should  be  increased  about  one-seventh.  The  trusses  may 
be  placed  ten  feet  apart;  and  the  rafters,  two  by  eight 
inches,  notched  two  inches  below  the  top  of  the  curved 
rib.  The  purlins  at  aaa  should  be  six  by  six  inches: 
they  are  designed  to  give  firmness  to  the  roof  at  the 
joints.  The  bearings  at  bb,  &c.,  are  of  cast  iron. 

Fig.  2  shows  a  design  for  a  roof  of  from  seventy  to  a 
hundred  and  twenty-five  feet  span.  It  is  so  designed, 
that  a  room  may  be  finished  above  the  tie-beams. 
If  the  span  be  great,  with  a  room  as  proposed,  the  cen- 
tre of  the  beam  between  the  rods  must  be  trussed,  as 
shown  in  the  examples  on  Plate  V. ;  and  the  floor-joists 
should  bridge  upon,  rather  than  cut  into,  the  tie-beams. 

It  will  be  seen,  by  an  examination  of  the  plate,  that  at 
the  line  AB  there  is  a  tie-beam,  which,  with  the  work 
above  it,  comprises  a  segmental  roof,  complete  in  itself; 
and  its  rise  may  be  increased  as  circumstances  require. 
The  dimensions  designated  by  the  figures  are  for  a  roof 
of  eighty  feet  span,  and  should  be  increased  one-eighth 
for  a  span  of  a  hundred  feet,  and  one-fifth  for  one  of  a 
hundred  and  twenty-five  feet,  —  the  rods  being  increased 
in  the  same  proportion. 


ROOFS 


Pl.X 


PI.  XI. 


ROOFS 


KOOFS.  119 


PLATE    XI. 

The  figures  on  this  plate  exhibit  the  design  of  a 
portion  of  the  large  trusses  which  support  the  dome  of 
the  State  Capitol  at  Montpelier,  Vt.*  The  span  is  sixty- 
seven  feet  four  inches  between  the  walls,  and  the  trusses 
receive  no  support  from  below.  The  bearing-pieces  are 
of  white  oak,  the  rest  of  the  timber  being  spruce.  Each 
truss  is  composed  of  two  parts,  or  sections,  like  those  re- 
presented by  the  designs.  The  beams  are  placed  fourteen 
inches  apart,  with  short  transverse  ones  extending  from 
one  to  the  other,  as  at  aa,  &c.,  with  another  crossing 
them,  as  sedh  at  A.  Upon  the  beams  last  named  stand 
the  posts  of  the  dome,  which,  when  finished,  will  be  forty- 
two  feet  in  diameter.  Its  frame  being  octagonal,  the  two 
front  and  two  rear  posts  are  nearer  together  than  the 
others,  and  consequently  require  a  differently  constructed 
truss.  The  student  will  readily  discover,  on  examination, 
the  manner  in  which  the  particular  strains  are  resisted 
by  the  several  parts  of  the  work. 

*  These  trusses,  together  with  the  framing  of  the  roof  and 
dome,  employing  eighty  thousand  feet  of  timber,  were  exe- 
cuted by  Mr.  Eobert  Gunnison,  the  master-carpenter,  under 
the  direction  of  Thomas  E.  Powers,  Esq.,  the  superintendent 
of  construction,  from  drawings  furnished  by  the  author  in 
1857. 


120  ROOFS. 


PLATE    XH. 

Fig.  1  of  this  plate  shows  the  design  of  a  roof  over 
the  Fitchburg  Depot  in  this  city.  It  was  executed  from 
drawings  furnished  by  Mr.  Charles  G.  Hall  in  the  year 
1848.  The  second  floor  of  the  building  (some  eighty  feet 
wide,  and  a  hundred  and  fifty  feet  long)  is  supported 
entirely  by  rods  from  the  tie-beams.  It  has  been  loaded 
with  people,  at  an  average  of  a  hundred  and  twenty-five 
pounds  to  the  square  foot,  without  any  settlement  what- 
ever. The  trusses  are  ten  feet  apart  from  centres. 

Fig.  2  shows  the  roof  of  the  Boston  and  Maine  Rail- 
road Depot,  in  Haymarket  Square,  Boston.  It  was 
executed  from  drawings  made  by  Mr.  Richard  Bond, 
architect  of  the  building.  The  trusses  are  twelve  feet 
apart  from  centres.  This  roof  remains  as  firm  in  every 
part  as  when  first  built;  and,  considering  the  quantity 
of  timber  used,  it  is  a  good  roof. 

The  figures  on  each  of  these  designs  exhibit  the  dimen- 
sions of  each  part  as  taken  from  actual  measurement. 


ROOFS 


pi.xa 


ROOFS 


Fig!. 
E H F 

~B 


Wg.2. 


Jt 

—---  -k'-^ef  D/  <^ 


Fig.5. 


Snith . Blnilu 


ROOFS.  121 


PLATE    XIH. 

Figs.  1,  2,  and  3  of  this  plate  exhibit  a  method  of 
drawing  the  angle-ribs  of  a  roof,  the  outline  of  which  is 
AH;  and  a  portion  of  the  plan,  DEFG.  Divide  BH 
into  any  number  of  parts,  as  1,  2,  3,  4,  and  draw  lines 
through  these  points  to  the  angle-line  FB.  From  the 
points  of  intersection,  on  and  at  right  angles  with  the 
line  last  named,  draw  abed  equal  to  1,  2, 3,  4,  measuring 
from  BH  to  AH.  Trace  a  line  through  the  points,  and 
the  angle-rib  is  formed. 

Fig.  5  illustrates  the  method  of  ascertaining  the  length 
and  back  of  the  angle-rafters  of  a  hip-roof. 

Let  AB  represent  the  pitch  of  the  roof.  From  C,  the 
corner  of  the  plan,  draw  CD ;  and  from  D  draw  DE  per- 
pendicular to  CD,  equal  to  AB  :  from  this  point  draw 
EC,  which  is  the  rafter  required.  To  determine  the  back 
of  the  rafter,  we  proceed  as  follows :  Draw  ab  perpen- 
dicular to  CD.  On  the  centre  c,  with  a  radius  Sc6  (the 
edge  of  the  rafter)  describe  the  semicircle  fed;  then  from 
e  draw  ea  and  eb,  which  will  be  the  angle  of  the  rafter 
at  e. 

Where  the  plan  of  a  roof  is  bounded  by  lines  which  are 
not  parallel,  it  is  the  usual  practice,  jn  order  that  the 
sides  of  the  roof  may  be  of  the  same  inclination,  to  trun- 
cate the  work,  as  shown  at  A,  Fig.  4. 


122  ROOFS. 


PLATE    XIV. 

Fig.  1  of  this  plate  exhibits  a  design  for  a  roof  of 
large  span.  The  figures  designate  the  dimensions  of  tim- 
ber for  a  span  of  eighty  feet.  With  a  proportionate 
increase  of  the  size  of  rods  and  timber,  it  may  with  safety 
be  extended  over  a  span  of  a  hundred  and  twenty-five 
feet.  The  beam  should  be  made  in  two  sections,  the 
centre  portion  between  the  rods  trussed,  and  an  oak- 
plank  three  inches  thick  bolted  to  the  top  of  the  beam, 
as  seen  at  AB. 


Fig.l 


n 


Kgr-2. 


IP 

E 


Rg.3. 


J 


123 


PARTITIONS. 


IN  cases  where  a  large  partition  cannot  have  a 
proper  support  from  below,  —  as,  for  example, 
where  it  stands  over  a  hall  or  large  room,  —  it 
should  be  trussed,  so  that  its  entire  weight  shall 
rest  on  the  points  of  support. 

Figs.  2  and  3,  Plate  XIV.,  exhibit  two  designs  for  par- 
titions, which  will  readily  be  understood  without  further 
explanation. 


124 


DOMES. 


To  frame  a  dome  is  one  of  the  simplest  branches 
of  the  art  of  carpentry.  It  was,  however,  till  a  late 
day,  thought  to  require  great  ingenuity  and  scientific 
skill. 

A  dome  is,  in  all  directions  from  the  centre  of 
its  plan,  an  arch :  hence  it  is  possessed  of  great 
strength ;  and,  if  properly  constructed,  its  lightness 
is  its  greatest  recommendation.  The  dome  of  the 
State  House  at  Boston  is  a  fine  specimen  of  framing. 
Its  span  is  fifty-one  feet,  its  height  from  the  floor 
nearly  the  same;  and,  with  the  exception  of  the 
four  posts  which  support  the  lantern,  no  timber  is 
used  larger  than  three  inches  thick,  and  twelve 
inches  wide.  Every  other  rib  is  at  the  base  of 
these  dimensions,  the  alternate  ones  being  two  by 
twelve  inches.  All  are  placed  three  feet  apart 
on  the  circle,  and  taper  to  about  eight  inches  wide 
at  the  top,  where  they  are  cut  against  a  curb, 


DOMES.  125 

being  there,  about  twelve  incnes  apart  from 
centres. 

The  scarfs  are  similar  to  Fig.  2,  Plate  XX.,  and 
are  bolted  together  with  bolts  half  an  inch  in  dia- 
meter, with  plank  two  inches  thick,  spiked  on  each 
side  of  the  ribs  over  the  scarfing. 

The  rough  boarding  is  horizontal ;  and,  after 
enduring  the  storms  of  more  than  half  a  century, 
the  structure  has  proved  itself  well  adapted  to  its 
intended  purpose.  Were  the  dome  larger,  the 
size  of  its  timbers  would  not  necessarily  have  been 
increased,  since  the  principles  of  the  arch  pervade 
the  whole.  A  more  complicated  framing  would  have 
detracted  from  its  merit  as  a  design,  since  all  that 
can  be  desired  is  accomplished  by  the  present  one ; 
and  so  simple  are  the  principles  involved,  that  it  has 
not  been  thought  necessary  to  illustrate  them  by  an 
engraving. 

Where  a  dome  rests  upon  a  high  drum,  like  that 
of  the  Capitol  at  Montpelier,  it  may  be  necessary, 
if  the  structure  stands  in  an  exposed  situation,  to 
provide  a  skeleton-frame  of  posts,  girts,  braces,  &c., 
in  order  to  strengthen  the  work. 


BRIDGES    AND    CENTERINGS. 


129 


BRIDGES. 


THE  designing  of  wooden  bridges  was  for  many 
years  intrusted  to  the  architect,  but  has,  of  late, 
been  considered  as  more  properly  belonging  to  the 
engineer.  As  the  mechanical  part  of  bridge-build- 
ing must  be  done  by  the  carpenter,  a  few  examples 
are  given  in  illustration  of  his  province.  Most  of 
them  have  been  designed  for  this  work ;  and  those 
remarks  which  have  been  made  in  reference  to 
other  descriptions  of  framing  will  apply  equally 
well  to  this. 

9 


130  BRIDGES. 


PLATE    XV. 

Fig.  1  of  this  plate  represents  what  is  familiarly  known 
as  " Howe's  Bridge"  taking  its  name  from  its  inventor. 
The  stringers  A  and  B  are  of  planks  three  inches  thick, 
bolted  together.  These  planks  are  of  different  lengths ; 
and  the  joints  should  be  well  broken.  The  struts  cross 
each  other,  without  being  notched  or  cut  into ;  and,  at 
their  ends,  they  abut  against  a  piece  of  white  oak,  as  at  C, 
Fig.  2.  The  rods  are  two  in  number  to  each  section,  as  at 
DD,  Fig.  3.  The  height  of  the  sides,  or  trusses,  should 
be  about  one-twelfth  of  the  entire  length  of  the  span. 
The  stringers  should  be  wide  enough  to  come  out  flush 
with  the  sides  of  the  struts,  and  the  oak-pieces  must  be  as 
long  as  the  stringers  are  wide.  The  depth  of  the  stringer 
should  be  two-thirds  of  its  width;  and  the  struts  one- 
twelfth  the  height  of  the  truss,  measuring  between  the 
stringers  as  ef.  The  diameters  of  the  rods  should  be 
one-fourth  that  of  the  struts.  An  oak-piece,  two  inches 
thick  and  three  inches  and  a  half  wide,  is  put  at  the  nut 
at  each  end  of  the  rod,  as  at  g,  Fig.  3. 

Fig.  2  is  the  detail  of  the  work  at  F ;  and  Fig.  3,  a 
sectional  detail  of  that  on  the  line  HI.  The  figures  on 
the  engraving  denote  the  dimensions  of  timber  for  a 
bridge  a  hundred  feet  long,  eight  feet  high,  and  ten  feet 
wide  in  the  clear.  Should  a  wider  bridge  be  required, 
the  number  of  sections  must  be  increased.  It  is  often 
the  practice  to  place  the  floor-joists  on  the  top  of  the 
upper  stringer,  instead  of  below ;  in  which  case,  rails,  or  a 
balustrade,  will  be  required. 

Fig.  4  exhibits  a  design  for  a  short  bridge  of  from 
twenty-five  to  forty-five  feet  span.  It  is  made  by  placing 


BRIDGES.  131 

one  timber  above  another,  as  shown  in  the  drawing. 
The  timbers  being  inclined,  with  oak-keys  between  them, 
and  bolted  together,  a  very  strong  truss  is  formed.  The 
trusses  should  be  about  four  feet  apart,  and  the  floor- 
joists  three  inches  thick  and  twelve  inches  wide,  placed 
twenty  inches  apart.  These  dimensions  are  for  a  bridge 
of  thirty  feet  span. 

Fig.  5  exhibits  a  design  for  a  common  gallery  truss. 
The  bearing-pieces  should  be  of  oak. 

The  dimensions  are  for  a  truss  of  sixty  feet  span.  It 
may  be  made  somewhat  flatter,  if  desired,  and  still  be 
sufficiently  strong  for  practical  purposes. 


132  BRIDGES. 


PLATE    XVI. 

The  figures  on  this  plate  exhibit  designs  for  bridges  of 
from  fifty  to  ninety  feet  span.  Should  it  be  desired,  the 
floor-timbers  of  Fig.  2  may  be  placed  upon  the  centre 
rail,  and  the  work  above  them  will  answer  for  the  rails 
of  the  bridge :  if  this  be  done,  the  centre  rails  will  need 
additional  support  by  bracing.  The  dimensions  are  for 
bridges  of  sixty  feet  span ;  all  the  bearing-pieces  being 
of  the  best  dry  and  sound  white  oak,  bolted  with  five- 
eighth-inch  iron  bolts.  It  may  be  well  to  remark  here, 
that  the  floors  of  all  bridges  require  strong  horizontal 
braces  from  the  side-stringers,  crossing  each  other  at  the 
centre  in  order  to  prevent  vibration. 


BRIDGE  S 


PI.  AM 


i          1 


u 


•H 


^         L- 


A 


N 


F1.ZVE 


BRIDGES 


Kg.l. 


Kg.3. 


BRIDGES.  133 


PLATE    XVII. 

Fig.  1  represents  a  side-view  of  a  timber-bridge  over 
the  river  Meuse,  in  France.  Its  span  is  sixty  feet,  and  its 
width  twenty-eight  feet.  Each  arch  has  four  trusses. 

Fig.  2  exhibits  the  design  of  a  bridge  over  the  river 
Rhone,  in  France.  It  is  similar  in  principle  to  the  ex- 
ample at  Fig.  1,  the  trusses  being  secured  by  transverse 
timbers  bolted  together. 

Fig.  3  represents  a  bridge  over  the  river  Loiret,  near 
Orleans  in  France.  Its  span  is  sixty  feet,  and  its  width 
six  feet  six  inches. 

Fig.  4  shows  part  of  a  lattice-bridge  invented  by  Mr. 
Ithiel  Towne,  of  New  Haven,  Conn.  Its  span  may  be 
from  seventy-five  to  a  hundred  and  fifty  feet.  The  lattice- 
framing  is  of  planks  three  inches  thick,  and  twelve  inches 
wide,  so  arranged  as  to  cross  each  other  at  right  angles. 
They  are  confined  together  at  the  intersecting  parts  by 
oak  tree-nails,  an  inch  and  a  half  in  diameter,  passing 
through  each  of  the  planks.  The  depth  of  the  lattice- 
work should  be  about  an  eighth  of  the  entire  span. 
Plank-ribs  are  used  at  top  and  bottom  on  each  side  of 
the  lattice-work ;  the  sides  being  connected,  top  and 
bottom,  at  distances  of  twelve  feet,  by  cross-timbers, 
and  braced  horizontally  with  diagonal  braces.  A  bridge 
of  this  kind  exists  at  Philadelphia,  eleven  hundred  feet 
long,  resting  on  ten  stone  piers.  There  is  also  another 
on  the  New -York  and  Harlem  Railroad,  seven  hundred 
and  thirty-six  feet  long,  resting  on  but  four  piers. 


134 


BRIDGE-CENTERINGS. 


A  CENTERING  is  a  frame  of  timber  designed  to  sup- 
port the  stones  of  an  arch  while  building.  Where 
the  bed  of  the  river  is  not  very  deep,  nor  the  tide 
strong,  a  centering  may  be  made  at  small  expense ; 
but  in  other  circumstances,  and  where  the  span  is 
large,  a  more  complex  and  expensive  system  of 
framing  must  be  adopted. 

In  the  construction  of  a  centering,  the  principal 
object  is  so  to  arrange  the  timbers  that  a  weight  or 
pressure,  when  exerted  upon  any  particular  part, 
may  be  resisted,  and  the  structure  retain  its  original 
form  throughout ;  and  it  should  be  so  designed  as  to 
admit  of  removal  without  injury  to  the  work  rest- 
ing upon  it.  In  most  examples,  this  is  done  by  the 
insertion  of  a  piece  at  the  springing  points,  cut  on 
its  sides  into  a  series  of  inclined  planes  :  over  these, 
oak  wedges  are  driven,  which,  being  easy  of  re- 
moval, admit  the  uniform  releasing  of  every  part 
of  the  work. 


PI  XVlli 


CEMRES 


BRIDGE-CENTERINGS.  135 


PLATE    XVIII. 

Fig.  1  of  this  plate  exhibits  a  centre  designed  by  Mr. 
Smeaton,  architect  of  the  celebrated  Eddystone  Light- 
house. It  is  familiarly  known  as  the  "  Cold-Stream 
Centre,"  taking  its  name  from  the  river  over  which  the 
bridge  was  built.  The  span  of  the  large  or  middle  arch 
is  sixty  feet  eight  inches.  The  bridge  is  twenty-five  feet 
wide  outside ;  and,  in  its  construction,  five  centres  were 
used  to  each  arch. 

Fig.  2  exhibits  a  centre  used  in  building  the  arches  of 
a  railroad-bridge  over  the  river  Ouse,  near  York,  England. 
The  bridge  consists  of  three  arches,  each  sixty-six  feet 
span ;  the  soffit  of  the  arch  (or  width  of  bridge)  being 
twenty-eight  feet  seven  inches. 

Fig.  3  is  a  design  for  a  centre  given  by  Mr.  Tredgold, 
which  may  be  used  for  any  span  short  of  seventy-five  feet 


136  BRIDGE-CENTERINGS. 


PLATE    XIX. 

Fig.  1  exhibits  a  part  of  one  of  the  centres  used  in 
the  construction  of  London  Bridge.  It  was  designed  by 
Mr.  Rennie  in  1826.  The  width  of  the  bridge,  from  "  out 
to  out,"  is  fifty-six  feet.  The  middle  or  centre  one  of  its 
five  arches  is  a  hundred  and  fifty-two  feet  span,  and  has 
a  rise  of  twenty-nine  feet  six  inches.  Each  arch  used 
eight  centres,  composed  of  fir ;  the  springing-pieces  being 
of  elm,  and  the  striking-wedges  of  oak. 

Fig.  2  exhibits  the  design  of  a  centre  executed  by  Mr. 
Thomas  Telford  in  building  a  stone  bridge  at  Gloucester, 
England.  The  bridge  consists  of  a  single  arch  of  a 
hundred  and  fifty  feet  span,  with  a  rise  of  thirty-five 
feet.  It  is  thirty-five  feet  wide;  and  six  centres  were 
used,  connected  by  cross-bars  and  caps,  and  the  whole 
steadied  by  diagonal  braces.  Between  the  timber  which 
rested  on  the  top  of  the  piles,  and  the  lower  horizontal 
timber  of  each  centre,  were  placed  the  wedges,  which, 
being  driven  back,  slackened  it  after  the  stone-work  was 
completed.  The  piles  were  of  Memel  fir,  shod  with  iron 
at  each  end,  and  the  remainder  of  the  work  of  Dantzic 
fir ;  the  whole  being  fifteen  inches  square.  Each  centre 
was  framed  entire ;  and  then,  by  the  aid  of  barges  and  two 
cranes  on  the  shore,  was  lifted  into  its  place. 

Fig.  3  exhibits  a  centering,  simple  in  construction,  but 
of  great  utility.  It  may  be  employed  to  advantage  wher- 
ever the  bed  of  the  river  can  be  used,  and  the  tide  is  not 
too  strong;  and  for  any  span  from  a  hundred  to  two 
hundred  feet. 


Fi.HX 


Snridi.Kiaght  8c  Tampan .  Emgt1 


JOINTS,  IRON-WORK,  AND 
TIMBER-TABLES. 


139 


JOINTS   IN   FRAMING. 


NOTHING  is  more  essential  to  the  permanency  of 
a  piece  of  carpentry  than  properly  made  .joints. 
If  the  parts  do  not  so  fit  together  that  each  may 
have  its  full  bearing,  the  structure  will  inevitably 
be  weak.  The  examples  on  this  plate  are  designed 
to  represent  in  detail  the  best  manner  of  forming 
joints  of  the  various  kinds  most  in  use. 


140  JOINTS    IN    FRAMING. 


PLATE    XX. 

Fig.  1  represents  the  framing  at  the  foot  of  the  rafters 
of  Fig.  1,  Plate  XIV.  abed  is  a  cast-iron  shoe,  or  box- 
ing. AAA  are  oak-keys,  two  inches  square.  BB  are 
wrought-iron  straps,  in  place  of  which  bolts  may  be 
used  if  desired. 

Fig.  2  exhibits  the  method  of  splicing  an  upright 
timber;  as,  for  instance,  a  tower-post.  The  length  of 
such  a  splice  should  be  three  times  the  diameter  of  the 
stick,  and  bolted  together  with  half  or  five-eighth  inch 
bolts. 

Fig.  3  illustrates  a  method  of  framing  work  at  the 
foot  of  the  rafters  of  a  common  roof.  This  method  is 
much  used.  Each  timber  is  to  be  notched  into  a  half- 
inch  to  receive  the  purlin. 

Fig.  4  shows  the  manner  of  framing  a  centre-bearing 
like  that  at  A,  Fig.  2,  Plate  VII. ;  or  B,  Fig.  5,  Plate  XV. 

Fig.  5  exhibits  the  method  of  framing  the  foot  of  the 
rafters  in  a  roof  having  inclined  beams,  as  the  example 
on  Plate  VIII. 

Fig.  6  shows  the  detail  of  a  piece  of  framing,  as  at 
AB,  Fig.  1,  Plate  VII.  At  A  is  an  oak-key  two  inches 
square. 

Fig.  7  is  the  detail  of  framing  at  the  intersection  C  of 
the  plate  before  referred  to ;  E  being  a  wrought-iron 
strap,  three-eighths  of  an  inch  thick  and  three  inches 
wide,  made  in  two  parts,  with  shoulders,  and  a  small  bolt 
at  a  for  securing  the  work. 


: 


fig.3. 


141 


IRON. 


As  cast  and  wrought  iron  are  used  in  all  heavy 
framing,  a  few  pages  of  this  work  will  be  devoted 
to  a  consideration  of  its  nature  and  properties. 

Iron  is  a  metal  found  in  nearly  all  parts  of  the 
world.  Its  specific  gravity  is  .7632 ;  being,  with 
the  exception  of  tin,  the  lightest  of  all  metals :  and 
it  differs  from  them  all  in  the  fact,  that,  while  they 
are  made  brittle  by  the  action  of  heat,  its  mallea- 
bility is  thereby  greatly  increased. 

Iron  shrinks  so  much  in  cooling,  that  a  pattern 
for  castings  should  be  made  an  eighth  of  an  inch 
larger  per  foot  than  the  piece  is  required  to  be 
when  cooled.  It  is  heated  so  as  to  appear  red  in 
the  dark  at  752°  Fahrenheit ;  and,  in  twilight,  at 
884°.  It  is  made  visibly  red-hot  by  day  at  1,077°, 
and  is  thoroughly  melted  at  2,754°. 

Cast  iron  expands  T^sWtf  °f  *ts  length,  in  each 
direction,  for  every  degree  of  heat ;  and  its  greatest 


142  IRON. 


expansion  is  T^TF  °f  ^ts  length  in  the  shade,  and 
TuVo-  °f  its  length  when  exposed  to  the  sun.  It 
will  bear  an  extension  of  T^^  of  its  length  with- 
out permanent  or  serious  alteration. 

Wrought  iron  expands  T4sW^  °f  its  length  for 
each  degree  of  heat.  It  will  bear  an  extension  of 
TiVo^  °f  its  length,  and  a  pressure  of  17,800  pounds 
to  a  square-inch,  without  injury.  Its  cohesive 
power  is  diminished  ^^TF  ^7  every  degree  of 
heat. 

The  resisting  power  of  cast  iron  has  been  greatly 
overestimated.  The  best  experiments  show  that  a 
force  of  93,000  pounds  to  a  square-inch  will  crush 
it,  and  that  it  will  not  bear  more  than  15,300 
pounds  without  visible  alteration. 

The  tensile  strength  of  wrought-iron  rods  has 
been  tested  in  a  variety  of  ways.  It  has  been 
decided  that  no  particular  amount  can  be  named  as 
the  actual  strain  a  rod  will  resist,  as  it  has  been 
repeatedly  proved  that  no  rod  is  to  be  depended 
upon  as  uniformly  perfect  throughout,  a  lesser 
strain  often  parting  a  rod  of  larger  diameter.  The 
cohesive  power  of  cast  iron  is  set  down  by  most 
authors  at  40,000,  and  of  wrought  iron  at  60,000, 
ppunds  to  a  square-inch.  A  vertical  rod,  having  a 
weight  suspended  at  the  lower  end  as  in  the  case 


IRON. 


143 


of  rods  supporting  a  tie-beam,  not  only  supports 
the  weight  at  the  end,  but  must,  in  addition,  sustain 
its  .own  weight  from  the  point  at  which  it  is  sus- 
pended ;  so  that  a  long  rod  will  part  near  the  upper 
sooner  than  the  lower  end.  A  perfect  rod,  there- 
fore, decreases  in  strength  as  it  is  longer,  and  vice 
versa.  The  iron-work  in  the  examples  of  framing 
given  in  this  work  is  so  figured  as  properly  to  sup- 
port the  work,  and,  at  the  same  time,  prevent  un- 
necessary vibration. 

The  following  table  shows  the  weight  of  a 
square-foot  of  cast  or  wrought  iron  plate,  from 
a  sixteenth  of  an  inch  to  an  inch  in  thickness, 
advancing  by  sixteenths :  — 


Dimens.     Wrought. 

Cast. 

Dimens. 

Wrought. 

Cast. 

16ths. 

Ibs. 

Ibs. 

leths. 

Ibs. 

Ibs. 

1 

2.5 

2.3 

9 

22.8 

21.1 

2 

5.1 

4.7 

10 

25.4 

23.5 

3 

7.6 

7.0 

11 

27.9 

25.8 

4 

10.1 

9.4 

12 

30.4 

28.1 

5 

12.7 

11.7 

13 

32.9 

30.5 

6 

15.2 

14.0 

14 

35.5 

32.9 

7 

17.9 

16.4 

15 

38.0 

35.2 

8 

20.3 

18.0 

16 

40.6    • 

37.6 

144 


IRON. 


The  following  table  shows  the  weight  of  a  foot 
in  length  of  wrought  or  cast  iron,  either  round  or 
square,  from  half  an  inch  to  three  inches  in  dia- 
meter, advancing  by  eighths  :  — 


WROUGHT. 

CAST. 

Side  of  Square 
or  Diameter. 

Circular. 

Square. 

Side  of  Square 
or  Diameter. 

Circular. 

Square. 

Inches. 

Ibs. 

Ibs. 

Inches. 

Ibs. 

Ibs. 

£ 

.65 

.83 

k 

.61 

.78 

& 

1.02 

1.3 

ft 

.95 

1.22 

| 

1.47 

1.87 

4 

1.38 

1.75 

| 

2. 

2.55 

I 

1.87 

2.39 

1 

2.61 

3.33 

1 

2.45 

3.12 

1J 

3.31 

4.21 

H 

3.1 

3.95 

14 

4.09 

6.2 

4 

3.83 

4.88 

If 

4.94 

6.3 

i§ 

4.64 

5.9 

1* 

5.89 

7.5 

i| 

5.52 

7.03 

If 

6.91 

8.6 

it 

648 

8.25 

11 

8.01 

10.2 

14 

7.51 

9.57 

If 

9.2 

11  71 

11 

8.62 

10.98 

2 

10.47 

13.33 

2 

9.81 

12.5 

2| 

11.82 

15.05 

2£ 

11.08 

14.11 

24 

13.25 

16.87 

12.42 

15.81 

2| 

14.76 

18.8 

2f 

13.84 

17.62 

24 

1636 

20.8 

24 

15.33 

19.53 

1 

18.03 
19.79 
21.63 

22.96 
25.2 
27.55 

2| 
24 
2§ 

16.91 
18.56 
20.28 

21.53 
23.63 
25.83 

3 

23.56 

30. 

3 

22.08 

28.12 

A  cubic-foot  of  cast  iron  weighs  450.5  pounds ; 
and  one  of  wrought,  486.8.  A  cubic-inch  of  each 
weighs  respectively  .260  and  .281. 


IRON. 


145 


The  accompanying  table  shows  the  weight  of 
bar-iron  from  a  quarter  of  an  inch  to  an  inch  in 
thickness,  and  from  one  to  four  inches  in  width, 
advancing  by  an  eighth:  — 


Width  of 
Bar. 

Thick. 

4  in. 

Thick. 

fin. 

Thick. 

Jin. 

Thick. 

fin. 

Thick. 

,   fin- 

Thick, 
fin. 

Thick. 

lin. 

in. 

.84 

1.25 

1.66 

2.08 

2.5 

2.91 

3.31 

| 

.93 

1.4 

1.87 

2.34 

2.81 

3.28 

3.75 

^ 

.04 

1.56 

2.08 

2.6 

3.12 

3.64 

4.16 

a 

.14 

1.71 

2.29 

2.86 

3.4 

4.01 

4.58 

| 

.25 

1.87 

2.5 

3.12 

3.75 

4.37 

5. 

| 

.35 

2.03 

2.71 

3.38 

4.11 

4.73 

5.42 

I 

.45 

2.18 

2.91 

3.64 

4.37 

5.1 

.   5.83 

1| 

.66 

2.34 

3.12 

3.90 

4.73 

5.46 

6.25 

2 

.77 

2.5 

3.33 

4.16 

5. 

5.83 

6.66 

2| 

.87 

2.21 

3.54 

4.42 

5.36 

6.19 

7.08 

2-i 

.98 

2.81 

3.75 

4.68 

5.62 

6.56 

7.5 

2| 

2.08 

2.97 

3.96 

4.94 

5.98 

6.92 

7.91 

24 

2.18 

3.12 

4.1G 

5.2 

6.25 

7.29 

8.33 

2| 

2.29 

3.28 

4.37 

5.46 

6.61 

7.65 

8.75 

21 

2.4 

3.43 

4.58 

5.72 

6.87 

8.02 

9.16 

2& 

2.5 

3.59 

4.79 

5.98 

7.26 

8.38 

9.58 

3 

2.6 

3.75 

5. 

6.25 

7.5 

8.75 

10. 

3J 

2.7 

3.91 

5.21 

6.51 

7.86 

9.11 

10.42 

34 

2.81 

4.06 

5.41 

6.77 

8.12 

9.47 

10.83 

3| 

2.91 

4.22 

5.62 

7.03 

8.39 

9.83 

11.24 

3| 

3.01 

4.37 

5.83 

7.29 

8.75 

10.2 

11.66 

3| 

3.11 

4.56 

6.04 

7.55 

9.10 

10.56 

12.08 

3| 

3.22 

4.68 

6.25 

7.81 

9.37 

10.93 

12.5 

3J 

3.30 

4.84 

6.46 

8.07 

9.64 

11.30 

12.92 

4 

3.34 

5. 

6.66 

8.32 

10. 

11.66 

13.33 

The  weights  in  the  foregoing  tables  are  those  of 
English  iron.  American  iron  is  a  seventieth  heavier; 
and  therefore,  in  making  calculations  of  its  weight,  one 
pound  should  be  added  to  every  seventy  pounds  as  com- 
puted by  the  tables. 

To  ascertain  the  weight  of  any  piece  of  cast  iron,  we 
have  but  to  determine  the  contents  in  cubic  inches,  and 
10 


146  IRON. 

multiply  it  by  the  decimal  .260 ;  or  in  feet,  and  multiply 
by  450.5.  If  it  be  of  a  shape  or  form  that  will  readily 
admit  of  measurement  in  superficial  feet  as  plates,  we 
select  the  multiplier  for  the  particular  thickness  as  given 
in  the  table,  and  the  product  is  the  weight  in  pounds. 

To  determine  the  weight  of  a  piece  of  wrought  iron, 
we  ascertain  its  contents  in  cubic  inches,  and  multiply  it 
by  the  decimal  .281 ;  'or  in  feet,  and  multiply  by  486.8; 
or,  if  it  admits  of  measurement  as  a  plate,  multiply  the 
amount  of  superficial  feet  by  the  figures  set  against  the  par- 
ticular thickness  in  the  table.  To  determine  the  weight 
of  any  piece  of  round,  square,  or  flat  iron,  we  select  the 
amount  given  in  the  table,  and  multiply  it  by  the  number 
of  feet  in  length  of  the  piece  whose  weight  we  wish 
to  obtain. 


147 


TABLES  OF  TIMBER-MEASURE. 


THE  accompanying  tables  exhibit  the  scantling,  or  dimensions, 
of  building-timber  reduced  to  board-measure.  The  figures 
in  the  left-hand  column  of  each  section  represent  the  length  of 
the  piece  in  feet;  those  of  the  right-hand  column,  the  contained 
quantity  in  feet  and  inches ;  and  those  over  the  head  of  each 
section,  the  thickness  and  depth  of  the  piece  in  inches.  The 
decimals  denote  twelfths  of  a  foot.  Thus,  a  stick,  seven  by 
nine  inches  square  and  nine  feet  long,  contains  forty-seven 
feet  and  three-twelfths  of  a  foot. 

If  it  is  desired  to  know  the  quantity  contained  in  sticks  of 
greater  length  than  those  given  in  the  tables,  this  may  be 
ascertained  by  adding  the  amount  of  two  or  more  requisite 
lengths  together. 


2X2 

2X3 

2X4 

! 

2X5 

2X6 

1                 . 

1 

0.4 

li      0.6 

li     0.8 

1 

0.10 

1 

1. 

2 

0.8 

2        1.           -1 

1.4    i 

2 

1.8 

2 

2. 

3 

1. 

3i      1.6 

!    3 

2. 

3 

2.6 

3 

3. 

4 

1.4 

4        2. 

j    4 

2.8    | 

4 

3.4 

4 

4. 

5 

1.8 

5 

2.6 

i    5 

3.4 

5 

4.2 

5 

5. 

6 

2. 

6 

3. 

!    6 

4. 

6 

5. 

6 

6. 

7 

2.4 

7 

3.6 

7 

4.8 

7 

5.10 

7 

7. 

8 

2.8 

* 

4. 

8 

5.4 

8 

6.8 

8       8. 

9 

3. 

9 

4.6 

9 

6. 

9 

7.6 

9       9. 

10 

3.4 

10 

5. 

10 

6.8 

10 

8.4 

10 

10. 

11 

3.8 

11 

5.6 

11 

7.4 

11 

9.2 

11 

11. 

12 

4. 

12 

6. 

12 

8. 

12 

10. 

12 

12. 

13 

4.4 

i:; 

6.6 

!13 

8.8 

13 

10.10 

13 

13. 

14 

4.8 

14 

7. 

14 

9.4 

14      11.8 

14 

14. 

15 

5. 

15 

7.6 

15      10. 

15 

12.6 

15 

15. 

16 

5.4 

16        8. 

16      10.8 

16 

13.4 

16 

16. 

17 

5.8 

17 

8.6 

17 

11.4 

17 

14.2    i 

17 

17. 

18 

6. 

18 

9. 

•18 

12. 

18 

15. 

18 

18. 

19  i      6.4 

19 

9.6 

19 

12.8 

19 

15.10 

19      19- 

20  i      6.8    i 

20 

10. 

20      13.4 

20      16.8    | 

20  i    20- 

148 


TABLES    OF   TIMBER-MEASURE. 


2X7 

2X8 

2X9 

2X10 

2X11 

1 

1.2 

1 

1.4 

1 

1.6 

1 

1.8 

1 

1.10 

2 

2.4 

2 

2.8 

2 

3. 

2 

3.4 

2 

3.8 

3 

3.6 

3 

4. 

3 

4.6 

3 

5. 

3 

5.6 

4 

4.8 

4   5.4 

4 

6. 

4 

6.8 

4 

7.4 

5 

5.10 

5 

6.8 

5 

7.6 

5 

8.4 

5 

9.2 

6 

7. 

6 

8. 

6 

9. 

6 

10. 

6 

11. 

7 

8.2 

7   9.4 

7 

10.6 

7 

11.8 

7 

12.10 

8 

9.4 

8   10.8 

8 

12. 

8 

13.4 

8 

14.8 

9 

10.6 

1  9i  12. 

9 

13.6 

9 

15. 

9 

16.6 

10 

11.8 

10   13.4 

10 

15. 

10 

16.8 

10 

18.4 

11 

12.10 

11   14.8 

11 

16.6 

11 

18.4 

11 

20.2 

12 

14. 

12   16. 

12 

18. 

112 

20. 

12 

22. 

13 

15.2 

13   17.4 

13 

19.6  1  13 

21.8  i  13 

23.10 

14 

16.4 

14   18.8 

14 

21. 

14 

23.4   14 

25.8 

15 

17.6 

<  15   20. 

15 

22.6 

15 

25.   I  15 

27.6 

16 

18.8 

16   21.4 

16 

24. 

16 

26.8  !  16 

29.4 

17 

19.10 

17   22.8 

17 

25.6 

17 

28.4 

17 

31.2 

18 

21. 

18   24. 

18 

27. 

18 

30. 

18 

33. 

19 

22.2 

j  19   25.4 

19 

28.6 

19 

31.8 

19 

34.10 

20 

23.4 

20 

26.8 

20 

30. 

20 

33.4 

20 

36.8 

2X12 

2X13 

2X14 

3X3 

3X4 

1 

2. 

1 

2.2 

1 

2.4 

1 

0.9 

1 

1. 

2 

4. 

2 

4.4 

2 

4.8 

2 

1.6 

2 

2. 

3 

6. 

3 

6.6 

3 

7. 

3 

2.3 

3 

3. 

4 

8. 

4 

8.8 

4 

9.4 

4 

3. 

4 

4. 

5 

10: 

5 

10.10 

5 

11.8 

5 

3.9 

5 

5. 

6 

12. 

6 

13. 

6 

14. 

6 

4.6 

6 

6. 

7 

14. 

7 

15.2 

7 

16.4 

7 

5.3 

r 

7. 

8 

16. 

8 

17.4 

8 

-  18.8 

8 

6. 

8 

8. 

9 

18. 

9 

19.6 

9 

21. 

9 

6.9 

9 

9. 

10 

20. 

10 

21.8 

10 

23.4 

10 

7.6  : 

10 

10. 

11 

22. 

11 

23.10 

11 

25.8 

11 

8.3  j 

11 

11. 

12 

24. 

12 

26. 

12 

28. 

12 

9. 

12 

12. 

13 

26. 

13 

28.2 

13 

30.4 

13 

9.9 

13   13. 

14 

28. 

14 

30.4 

14 

32.8 

14 

10.6 

14   14. 

15 

30. 

15 

32.6 

15 

35. 

15 

11.3 

15 

15. 

16 

32. 

16 

34.8 

16 

37.4 

16 

12. 

16 

16. 

17 

34. 

17 

36.10 

17 

39.8 

17 

12.9 

17 

17. 

18   36. 

18 

39. 

18 

42. 

18 

13.6 

18 

18. 

19 

38. 

19 

41.2 

19 

44.4 

19 

14.3 

19 

19. 

20 

40. 

20 

43.4 

20 

46.8 

20 

15. 

20 

20. 

TABLES    OF    TIMBER-MEASURE. 


149 


3X5 

3X6 

3X7 

3X8 

3X9 

1 

1.3 

1   1.6 

1   1.9 

1 

2. 

1 

2.3 

2 

2.6 

2   3. 

2!   3.6 

2 

4. 

1  2 

4.6 

3 

3.9 

3!   4.6 

3    5.3 

3 

6. 

'   3 

6.9 

4 

5. 

4|   6. 

4   7. 

4 

8. 

4 

9. 

5 

6.3 

5   7.6 

5   8.9 

5 

10. 

5 

11.3 

6 

7.6 

6    9. 

6   10.6 

6 

12. 

6 

13.6 

7 

8.9 

7 

10.6 

7   12.3 

7 

14. 

7 

15.9 

8 

10. 

- 

12. 

8   14. 

8 

16. 

!  8 

18. 

9 

11.3 

9 

13.6 

9   15.9 

9 

18. 

;  9 

20.3 

10 

12.6 

10 

15. 

;10   17.6   10 

20. 

10 

22.6 

11 

13.9 

11 

16.6 

11  !  19.3 

11 

22. 

11 

24.9 

12 

15. 

12 

18. 

'  12  !  21. 

12 

24. 

12 

27. 

13 

16.3 

13 

19.6 

•  13   22.9   13 

26. 

13 

29.3 

14 

17.6 

14 

21. 

14   24.6 

14 

28. 

14 

31.6 

15 

18.9 

15 

22.6 

15   26.3 

15 

30. 

15 

33.9 

16 

20. 

16 

24. 

i!6i  28.    l»; 

32. 

16 

36. 

17 

21.3 

17 

25.6 

17 

29.9 

17 

34. 

17 

38.3 

18 

22.6 

18 

27. 

!18 

31.6 

18 

36. 

18 

40.6 

19 

23.9 

19 

28.6 

19 

33.3 

19 

38. 

19 

42.9 

20  |  25. 

20 

30. 

20 

35. 

20 

40. 

20 

45. 

1  

3X10 

3X11 

3X12 

3X13     3X14 

j 

1 

2.6 

1 

2/9 

1 

3. 

1!   3.3 

i  1 

3.6 

2 

5. 

2 

5.6 

2 

6. 

2   6.6 

;  2 

7. 

3   7.6 

3 

8.3 

I  3 

9. 

3   9.9 

3 

10.6 

4 

10. 

4 

11. 

4 

12. 

4   13. 

4 

14. 

5 

12.6 

5 

13.9 

5 

15. 

5   16.3 

5 

17.6 

6 

15. 

6 

16.6 

6 

18. 

6   19.6 

i  6 

21. 

7 

17.6 

7 

19.3 

7 

21. 

7;  22.9 

j  7 

24.6 

8 

20. 

8 

22. 

8 

24. 

1  8   26. 

i  8 

28. 

9 

22.6 

9 

24.9 

9 

27. 

,  9   29.3 

9 

31.6 

10 

25. 

10 

27.6 

ilO 

30. 

10   32.6 

10 

35. 

11 

27.6 

11 

30.3 

111 

33. 

11   35.9 

11 

38.6 

12 

30. 

12 

33. 

12 

36. 

12   39. 

'12 

42. 

13 

32.6 

.13 

35.9 

13 

39. 

13   42.3 

13 

45.6 

14 

35. 

14 

38.6 

14 

42. 

14 

45.6 

14 

49. 

15 

37.6 

15 

41.3 

15 

45. 

15 

48.9 

115 

52.6 

16 

40. 

16 

44. 

16 

48. 

16 

52. 

16 

56. 

17 

42.6 

17 

46.9 

!17 

51. 

17 

55.3 

17 

59.6 

18 

45. 

18 

49.6 

!l8 

54. 

118 

58.6 

18 

63. 

19 

47.6 

19 

52.3 

19 

57. 

|19   61.9 

19 

66.6 

20 

60. 

20 

55. 

j  20   60. 

20   65. 

20 

70. 

150 


TABLES    OF   TIMBER-MEASURE. 


4X4 

4X5 

4X6 

4X7 

4X8 

1 

1.4 

1 

1.8 

1 

2. 

1 

2.4 

1 

2.8 

2 

2.8 

2 

3.4 

-2 

4. 

2 

4.8 

2 

5.4 

3 

4. 

3 

5. 

3 

6. 

3 

7. 

3 

8. 

4 

5.4 

4 

6.8 

4 

8. 

4 

9.4 

4 

10.8 

5 

6.8 

5 

8.4 

5 

10. 

5 

11.8 

5 

13.4 

6 

8. 

6 

10. 

6 

12. 

6 

14. 

6 

16. 

7 

9.4 

K 

11.8 

7 

14. 

7 

16.4 

7 

18.8 

8 

10.8 

8 

13.4 

8 

16. 

8 

18.8 

8 

21.4 

9 

12. 

9 

15. 

9 

18. 

9 

21. 

9 

24. 

10 

13.4 

10 

16.8 

10 

20. 

10 

23.4 

10 

26.8 

11 

14.8 

11 

18.4 

11 

22. 

11 

25.8 

11 

29.4 

12 

16. 

12 

20. 

12 

24. 

12 

28. 

12 

32. 

13 

17.4 

13 

21.8 

13 

26. 

13 

30.4 

13 

34.8 

14 

18.8 

[14 

23.4 

14 

28. 

14 

32.8 

14 

37.4 

15 

20. 

15 

25. 

15 

30. 

15 

35. 

15 

40. 

16 

21.4 

lie 

26.8 

16 

32. 

16 

37.4 

16 

42.8 

17 

22.8 

17 

28.4 

17 

34. 

17 

39.8 

17 

45.4 

18 

24. 

18 

30. 

18 

36. 

18 

42. 

18 

48. 

19 

25.4 

19 

31.8 

19 

38. 

19 

44.4 

19 

50.8 

20 

26.8 

20 

33.4 

20 

40. 

20 

46.8 

20 

63.4 

4X9 

4X10 

4X11 

4X12 

4X13 

1 

3. 

1 

3.4 

1 

3.8 

1 

4. 

1 

4.4 

2 

6. 

2 

6.8 

2 

7.4 

2 

8. 

2 

8.8 

3 

9. 

3 

10. 

3 

11. 

3 

12. 

3 

13. 

4 

12. 

4 

134 

4 

14.8 

4 

16. 

4 

17.4 

6 

15. 

5 

16-8 

5 

18.4 

5 

20. 

5 

21.8 

6 

18. 

6 

20. 

6 

22. 

6 

24. 

6 

26. 

7 

21. 

7 

23-4 

7 

25.8 

7 

28. 

7 

30.4 

8 

24. 

8 

26-8 

8 

29.4 

8 

32. 

8 

34.8 

9 

27. 

9 

30. 

9 

33. 

9 

36. 

9 

39. 

10 

30. 

10 

33.4 

10 

36.8 

10 

40. 

10 

43.4 

11 

33. 

11 

36-8 

11 

40.4 

11 

44. 

11 

47.8 

12 

36. 

12 

40. 

12 

44. 

12 

48. 

12 

52. 

13 

39. 

13 

43.4 

13   47.8  | 

13 

52. 

13 

56.4 

14 

42. 

14 

46.8 

14 

51.4 

14 

56. 

14 

60.8 

15 

45. 

15 

50. 

15 

55. 

15 

60. 

15 

65. 

16 

48. 

16 

53.4 

16   58.8 

16 

64. 

16 

69.4 

17 

51. 

17 

56.8 

17   62.4 

17 

68. 

17 

73.8 

18 

54. 

18 

60. 

18   66.  . 

18 

72. 

18 

78. 

19 

57.   1  19 

63.4 

19   69.8 

19 

76. 

19 

82.4 

20 

60.    20 

66.8  | 

20   73.4  i 

20 

80. 

20 

86.8 

[I 

I 

TABLES    OF   TIMBER-MEASURE. 


151 


4X14 

5X5 

5X6      5X7 

5X8 

1 

4.8 

1   2.1 

1 

2.6 

1 

2.11  !  1  i   3.4 

2 

9.4 

!  2   4.2 

2 

5. 

2 

5.10  i  2  i   6.8 

3 

14. 

!  3   6.3 

3 

7.6 

3 

8.9    3   10. 

4 

18.8 

4 

8.4 

4|  10. 

4 

11.8 

4   13.4 

5 

23.4 

5   10.5 

5 

12.6 

5 

14.7 

5 

16.8 

6 

28. 

6   12.6 

6 

15. 

6 

17.6 

6 

20. 

7 

32.8 

71  14.7 

7 

17.6  !  7 

20.5 

7 

23.4 

8 

37.4 

8 

16.8 

8 

20. 

8 

23.4 

i  8 

26.8 

9   42. 

9 

18.9 

9 

22.6 

9 

26.3 

!   9 

30. 

10  '  46.8 

10 

20.10  10 

25. 

10 

29.2 

10 

33.4 

11 

51.4 

11   22.11 

11 

27.6   11 

32.1 

11 

36.8 

12 

56. 

12   25. 

12   30.    12 

35. 

12 

40. 

13 

60.8 

13 

27.1 

13   32.6 

13 

37.11 

!l3 

43.4 

14 

65.4 

14 

29.2 

14 

35. 

14 

40.10 

14 

46.8 

15 

70. 

15   31.3 

15 

37.6 

'is 

43.9 

;15 

50. 

16 

74.8 

16 

33.4 

16 

40. 

16 

46.8 

16 

53.4 

17 

79.4 

17 

35.5 

17 

42.6 

!17 

49.7 

17 

56.8 

18 

84. 

18 

37.6 

18 

45. 

18 

52.6 

i!8 

60. 

19 

88.8 

19 

39.7 

19   47.6 

•19 

55.5 

19 

63.4 

20 

93.4 

20 

41.8 

20 

50. 

?20 

58.4 

;20 

66.8 

SX9 

5X10 

5X11 

i 

5X12 

5X13 

1 

3.9 

1 

4.2 

1 

4.7 

1   5. 

1  1 

5.5 

2 

7.6 

2 

8.4 

2 

9.2 

2   10. 

^  2 

10.10 

3 

11.3 

3 

12.6 

3 

13.9 

3   15. 

3 

16.3 

15. 

4 

16.8 

4 

18.4 

4  20. 

4 

21.8 

5   18.9 

5 

20.10 

5 

22.11 

5   25. 

;  5 

27.1 

6   22.6 

6 

25.   l!  6 

27.6 

6L  30. 

i  6 

32.6 

7   26.3 

7   29.2 

7   32.1 

7  35. 

7 

37.11 

8   30. 

8   33.4 

8   36.8 

8   40. 

8   43.4 

9   33.9 

9   37.6    9   41.3 

9  45. 

1  9   48.9 

10   37.6 

10 

41.8  !  10   45.10  10   50. 

1  10   54.2 

11  >  41.3   11 

45.10  11 

50.5  '  11   55. 

;  11   59.7 

12|  45. 

12 

50.    12 

55.   i  12   60. 

1  12   65. 

13  i  48.9 

13   54.2 

13   59.7  113,  65. 

1  13   70.5 

14   52.6   14   58.4 

14!  64.2   14   70.    14   75.10 

15 

56.3   15   62.6   15   68.9   15   75.    15   81.3 

16 

60.    16   66.8   16   73.4  i  16   80.    16   86.8 

17 

63.9 

17  ;  70.10  17 

77.11  ;17 

85. 

17   92.1 

18 

67.6 

18   75.   !18 

82.6  |!18 

90. 

18   97.6 

19 

71.3 

19  |  79.2  ;  19 

87.1  ''19 

95. 

19  102.11 

20 

75. 

20  I  83.4   20 

1   II 

91.8  j  20 

100. 

20 

108.4 

152 


TABLES    OF    TIMBER-MEASURE. 


5X14 

6X6 

6X7 

6X8 

6X9 

1   5.10 

1 

3. 

1 

3.6 

1 

4. 

1 

4.6 

2  i  11.8 

2|   6. 

2 

7. 

2 

8. 

2 

9. 

3 

17.6 

3 

9. 

3 

10.6 

3 

12. 

3 

13.6 

4 

23.4 

!  4 

12. 

4 

14. 

4 

16. 

4 

18. 

5 

29.2 

5 

15. 

6 

17.6 

5 

20. 

5 

22.6 

6 

35. 

6 

18. 

6 

21. 

6 

24. 

6 

27. 

7 

40.10 

7 

21. 

7 

24.6 

7 

28. 

7 

31.6 

8 

46.8 

8 

24. 

8 

28. 

8 

32. 

8 

36. 

9 

52.6 

9 

27. 

9 

31.6 

9 

36. 

9 

40.6 

10 

58.4 

10 

30. 

10 

35. 

10 

40. 

10 

45. 

11 

64.2 

11 

33. 

11 

38.6 

11 

44. 

11 

49.6 

12 

70. 

12 

3*6. 

12 

42. 

12 

48. 

12 

54. 

13 

75.10 

13 

39. 

13 

45.6 

113 

52. 

13 

68.6 

14 

81.8 

14 

42. 

14 

49.    14 

56. 

14 

63. 

15 

87.6 

15 

45. 

15 

52.6 

15 

60. 

15 

67.6 

16 

93.4 

16 

48. 

16 

56. 

16 

64. 

16 

72. 

17 

99.2 

17 

51. 

17 

59.6 

17 

68. 

17 

76.6 

18 

105. 

'18 

54. 

18 

63. 

18 

72. 

18 

81. 

19 

110.10 

19 

57. 

19   66.6 

19 

76. 

19 

85.6 

20 

116.8 

20 

60. 

20|  70.    20 

80. 

20 

90. 

1 

6X10 

6X11 

6X12 

6X13 

6X14 

1 

5. 

1 

5.6 

1 

6. 

1 

6.6 

1 

7. 

2 

10. 

2 

11. 

2 

12. 

2 

13. 

2 

14. 

3 

15. 

3 

16.6 

3 

18. 

3 

1  19.6 

3 

21. 

4 

20. 

4 

22. 

4 

24. 

4 

26. 

4 

28. 

5 

25. 

5 

27.6 

5 

30. 

5 

32.6 

5 

35. 

6 

30. 

6 

33. 

6 

36. 

6 

39. 

6 

42. 

7 

35. 

7 

38.6 

7 

42. 

7 

45.6 

7 

49. 

8 

40. 

8 

44. 

8 

48. 

8 

52. 

8 

56. 

9 

45. 

9 

49.6 

9 

54. 

9 

58.6 

9 

63. 

10 

50. 

10 

55. 

10 

60. 

10 

65. 

10 

70. 

11 

55. 

11 

60.6 

11 

66. 

11 

71.6 

11 

77. 

12 

60. 

12 

66. 

12 

72. 

12 

78. 

12 

84. 

13 

65. 

13 

71.6 

13 

78. 

13 

84.6 

13 

91. 

14 

70. 

14 

77. 

14 

84. 

14 

91. 

14 

98. 

15 

75. 

15 

82.6 

15 

90. 

15 

97.6 

15 

105. 

16 

80. 

16 

88. 

16 

96. 

16 

104. 

16 

112. 

17 

85. 

17 

93.6 

17 

102. 

17 

110.6 

17 

119. 

18 

90. 

18 

99. 

18 

108. 

18 

117. 

18 

126. 

19 

95. 

19 

104.6 

19 

114.    19 

123.6 

19 

133. 

20 

100. 

20 

110. 

20 

120. 

20 

130. 

20 

140. 

i             '  ' 

1       ; 

I 

i 

TABLES    OF    TIMBER-MEASURE. 


153 


'  i                      '                       '! 

7x7 

7X8 

7X9 

7X10             7X11 

1 

4.1 

!  i 

4.8         1 

5.3         1  ;      5.10       1        6.5 

2 

8.2 

2 

9.4 

2 

10.6 

2      11.8 

i    2      12.10 

3 

12.3 

3 

14. 

3 

15.9 

!    3 

17.6 

3      19.3 

4 

16.4 

4 

18.8         4 

21.           4      23.4         4      25.8 

5  I    20.5 

5 

23.4         5 

26.3         5      29.2     i    5      32.1 

6 

24.6 

6 

28. 

!    6 

31.6        6  :    35.          6      38.6 

7 

28.7 

7  i    32.8 

7 

36.9 

7 

40.10       7      44.11 

8 

32.8 

8 

37.4     '    8 

42. 

8 

46.8         8      51.4 

9 

36.9 

9 

42.       i    9 

47.3 

9 

52.6 

;  9 

57.9 

10 

40.10 

!10 

46.8       10 

52.6 

10 

58.4       10 

64.2 

11 

44.11 

111 

51.4     •  11 

57.9 

11 

64.2       11 

70.7 

12 

49. 

1  12 

56.       '  12 

63. 

12 

70. 

12 

77. 

13 

53.1 

113 

60.8       13 

68.3       13 

75.10     13 

83.5 

14 

57.2 

14 

65.4     I  14 

73.6 

14 

81.8      14 

89.10 

15 

61.3 

15 

70.       i  15 

78.9       l.j 

87.6       15 

96.3 

16 

65.4 

16 

74.8     !  16 

84.       i  16 

93.4 

16 

102.8 

17 

69.5 

17 

79.4     !  17 

89.3       17 

99.2 

;  1  f 

109.1 

18 

73.6 

18 

84.       i  18 

94.6 

18    105.         18 

115.6 

19 

77.7 

'19 

88.8     i  19 

99.9 

19    110.10  i  19 

121.11 

20 

81.8 

20 

93.4      20 

105.         20 

116.8 

j  20 

128.4 

7  X12 

7X13 

7x14 

8X8 

8X9 

1 

7. 

1 

7.7 

r    8.2 

1 

5.4 

1 

6. 

2 

14. 

2 

15.2 

2      16.4 

2 

10.8 

2 

12. 

3 

21. 

3 

22.9 

•    3      24.6 

3 

16. 

3 

18. 

4 

28. 

4 

30.4 

4      32.8 

4 

21.4 

4 

24. 

5 

35. 

5 

37.11 

1    5      40.10 

5      26.8 

5 

30. 

6 

42. 

6 

45.6 

6      49. 

6      32. 

i    6 

-36. 

7 

49. 

7 

53.1 

1    7      57.2 

7 

37.4 

1    1 

42. 

8 

56. 

8 

60.8 

8i    65.4 

8 

42.8 

8 

48. 

9 

63. 

9 

68.3        9      73.6 

9      48. 

!    9 

54. 

10 

70. 

'10 

75.10     10      81.8 

10      53.4 

10 

60. 

11 

77. 

111 

83.5    i  11      89.10     11 

58.8 

11 

66. 

12 

84. 

;  12 

91.         12      98.      jj  12 

64. 

12 

72. 

13 

91. 

;13 

98.7       13    106.2     !  13      69.4     i  13 

78. 

14 

98. 

14 

106.2       14    114.4 

14'    74.8    1,14      84. 

15 

105. 

!lo 

113.9    i  15    122.6 

15  i    80. 

15      90. 

16 

112. 

16 

121.4    i  16    130.8 

164    85.4 

16      96. 

17 

119. 

17 

128.11:  17    138.101117      90.8 

17  i  102. 

18 

126. 

18 

136.6    |j  181  147.        18 

96. 

18    108. 

19 

133. 

119 

144.1     1  19  I  155.2       19  j  101.4 

i  19  1  114. 

20 

140. 

20 

151.8    :  20    163.4      20  i  106.8 

i  20  !  120. 

i 

i 

154 


TABLES    OF   TIMBER-MEASURE. 


8X10 

8X11 

8X12             8X13 

8X14 

1 

6.8 

1 

7.4 

1 

8. 

1 

8.8 

1 

9.4 

2 

13.4 

2 

14.8 

2 

16. 

2 

17.4 

2 

18.8 

3 

20. 

3 

22. 

3 

24. 

3 

26. 

3 

28. 

4 

26.8 

4 

29.4 

4 

32. 

4 

34.8 

4 

37.4 

5 

33.4 

5 

36.8 

6 

40. 

5 

43.4 

5 

46.8 

6 

40. 

6 

44. 

6 

48. 

6 

52. 

6 

56. 

7 

46.8 

7 

51.4 

7 

56. 

7 

60.8 

7 

65.4 

8 

53.4 

8 

58.8 

8 

64. 

8 

69.4 

8 

74.8 

9 

60. 

9 

66. 

9 

72. 

9 

78. 

9 

84. 

10 

66.8 

10 

73.4 

10 

80. 

10 

86.8 

10 

93.4 

11 

73.4 

11 

80.8 

11 

88. 

11 

95.4 

111 

102.8 

12 

80. 

12 

88. 

12 

96. 

12 

104. 

12 

112. 

13 

86.8 

13 

95.4 

13 

104. 

13 

112.8 

13 

121.4 

14 

93.4 

1  14 

102.8 

14 

112. 

14 

121.4 

14 

130.8 

15 

100. 

15 

110. 

15 

120. 

15 

130. 

15 

140. 

16 

106.8 

16 

117.4 

16 

128. 

16 

138.8 

16 

149.4 

17 

113.4 

'17 

124.8 

17 

136. 

17 

147.4 

17 

158.8. 

18 

120. 

18 

132. 

18 

144.    i 

18 

156. 

18 

168. 

19 

126.8 

!l9 

139.4 

19 

152. 

19 

164.8 

19 

177.4 

20 

133.4 

20 

146.8 

20 

160. 

20 

173.4 

1 

20 

186.8 

9X9 

9X10 

9X11 

9X12 

9X13 

1 

6.9 

1 

7.6 

1 

8.3 

1 

9. 

1 

9.9 

2 

13.6 

2 

15. 

2 

16.6 

2 

18. 

2 

19.6 

3 

20.3 

3 

22.6 

3 

24.9 

3 

27. 

3 

29.3 

4 

27. 

4 

30. 

4 

33. 

4 

36. 

4 

39. 

5 

33.9 

1    5 

37.6 

5 

41.3 

5 

45. 

5 

48.9 

6 

40.6 

6 

45. 

6 

49.6 

6 

54. 

6 

58.6 

7 

47.3 

7 

52.6 

7 

57.9 

7 

63. 

7 

68.3 

8 

54. 

8 

60. 

8 

66. 

8 

72. 

8 

78. 

9 

60.9 

9 

67.6 

9 

74.3 

9 

81. 

9 

87.9 

10 

67.6 

10 

75. 

10 

82.6 

10 

90. 

10 

97.6 

11 

74.3 

11 

82.6 

11 

90.9 

11 

99. 

11 

107.3 

12 

81. 

12 

90. 

12 

99. 

12 

108. 

12  1  117. 

13      87.9 

:13 

97.6 

13 

107.3 

13 

117. 

13    126.9 

14  |    94.6 

114 

105. 

14    115.6 

14 

126. 

14  i  136.6 

15    101.3 

115 

112.6 

15 

123.9 

15 

135. 

15  I  146.3 

16  1  108. 

|16. 

120. 

16 

132. 

16 

144. 

16  !  156. 

17    114.9 

17 

127.6 

17 

140.3 

17 

153. 

17    165.9 

181121.6     '18 

135. 

18 

148.6 

18 

162. 

18    175.6 

19  !  128.3       19 

142.6 

19 

156.9 

19 

171. 

19    185.3 

20    135.         20 

150. 

20 

165. 

20 

180. 

20 

195. 

TABLES    OF   TIMBER-MEASURE. 


155 


9X14 

10X10 

10X11 

10X12 

10X13 

1 

10.6        1 

8.4 

1 

9.2 

1 

10. 

1 

10.10 

2 

21. 

i    2 

16.8 

2 

18.4 

2 

20. 

2 

21.8 

3 

31.6        3 

25. 

3 

27.6 

3 

30. 

3 

32.6 

4 

42. 

1    4 

33.4 

4 

36.8 

4 

40. 

4 

43.4 

5 

62.6         5 

41.8 

5 

45.10 

6 

50. 

5 

54.2 

6 

63.      !     6 

50. 

6 

55. 

60. 

6 

65. 

7 

73.6        7 

58.4 

7 

64.2 

7 

70. 

7 

75.10 

8 

84.          8 

66.8 

8 

73.4 

8     80. 

8 

86.8 

9 

94.6        9 

75. 

9 

82.6 

9      90. 

9 

97.6 

10 

105.       !  10 

83.4 

10 

91.8 

10  !  100. 

10 

108.4 

11 

115.6      11 

91.8 

11 

100.10 

11    110. 

11 

119.2 

12 

126. 

12 

100. 

12 

110. 

12    120. 

12 

130. 

13 

136.6 

13 

108.4 

13 

119.2 

13    130. 

13 

140.10 

14 

147.         14 

116.8 

14 

128.4 

14    140. 

14 

151.8 

15 

157.6       15 

125. 

15 

137.6 

15    150. 

15 

162.6 

16 

168. 

16 

133.4 

16    146.8 

16    160. 

16 

173.4 

17 

178.6 

17 

141.8 

17 

155.10 

17    170. 

17 

184.2 

18 

189. 

18 

150. 

18 

165.         18    180. 

IS 

195. 

19 

199.6 

19 

158.4 

19    174.2       19    190. 

19 

205.10 

20 

210. 

20 

166.8 

20    183.4    | 

20 

200. 

•1  > 

216.8 

10X14 

11X11 

11X12 

11X13 

11X14 

1 

11.8        1 

10.1 

1      11. 

1 

11.11 

1 

12.10 

2 

23.4 

;    2 

20.2 

2      22. 

2 

23.10 

•2 

25.8 

3 

35. 

3 

30.3 

3:    33. 

3 

35.9 

3 

38.6 

4 

46.8 

!    4 

40.4 

4      44. 

4 

47.8 

4 

51.4 

5 

58.4 

5 

50.5 

5i    55. 

5 

59.7 

5 

64.2 

6 

70. 

6 

60.6 

6      66. 

6 

71.6 

6 

77. 

7      81.8 

7 

70.7 

7 

77. 

7 

83.5 

7 

89.10 

8 

93.4 

8 

80.8 

8 

88. 

8 

95.4 

8    102.8 

9 

105. 

9 

90.9 

9      99. 

9    107.3 

9  j  115.6 

10 

116.8 

10 

100.10 

10    110. 

10  !  119.2 

10    128.4 

11 

128.4      11 

110.11 

11    121. 

11  i  131.1 

11    141.2 

12 

140. 

12 

121. 

12    132. 

12    143. 

12    154. 

13 

151.8       13 

131.1 

13    143.         13    154.11 

13  ,  166.10 

14 

163.4    JIM 

141.2 

14    154.       1141166.10 

14    179.8 

15 

175.      !  15 

151.3 

15    165. 

15  I  178.9 

15    192.6 

16 

186.8      16 

161.4 

16    176. 

16  1  190.8 

16    205.4 

17  |  198.4 

17 

171.5 

17    187. 

17  I  202.7 

17    218.2 

18 

210. 

;18 

181.6 

18    198. 

18    214.6 

18    231. 

19 

221.8      19 

191.7 

19    209. 

19    226.5 

19    243.10 

20 

233.4     j  20 

201.8 

20    220. 

20  ;  238.4 

20    256.8 

i 

156 


TABLES    OF   TIMBER-MEASURE. 


12X12 

12X13 

12X14 

12X15 

13X13 

1 

12. 

1 

13. 

1 

14. 

1 

15. 

1 

14.1 

2 

24. 

2      26. 

2 

28. 

2 

30. 

2 

28.2 

3 

36. 

3      39. 

3 

42. 

3 

45. 

3 

42.3 

4 

48. 

4|    52. 

4 

56. 

4 

60. 

4 

56.4 

5 

60. 

5      65. 

5 

70. 

5 

75. 

5 

70.5 

6 

72. 

6      78. 

6 

84. 

6 

90. 

6 

84.6 

7 

84. 

7      91. 

7 

98. 

7 

105. 

7 

98.7 

8 

96. 

8    104. 

8 

112. 

8 

120. 

8 

112.8 

9    108. 

9    117. 

ii 

126. 

9 

135. 

9 

126.9 

10  :  120. 

10    130. 

10 

140. 

10 

150. 

10 

140.10 

11    132. 

11    143. 

11 

154. 

11 

165. 

11 

154.11 

12    144. 

12    156. 

12 

168. 

12 

180. 

12    169. 

13  \  156. 

13    169. 

13 

182. 

13 

195. 

13    183.1 

14    168. 

14    182. 

14 

196. 

14 

210. 

14 

197.2 

15  !  180. 

15    195. 

15 

210. 

15 

225. 

15    211.3 

16    192. 

16    208. 

16 

224. 

16 

240. 

16 

225.4 

17  |  204. 

17    221. 

17 

238. 

17 

255. 

17 

239.5 

18  i  216. 

18    234. 

18 

252. 

18 

270. 

18 

253.6 

19    228. 

19    247. 

19 

266. 

19 

285. 

19 

267.7 

20 

240. 

20    260. 

20 

280. 

20 

300. 

20 

281.8 

13X14 

13X15 

14X14 

14X15 

14X16 

1 

15.2 

1 

16.3 

1 

16.4 

1 

17.6 

1 

18.8 

2 

30.4 

2 

32.6 

2 

32.8 

2 

35. 

2 

37.4 

3 

45.6 

3 

48.9 

3 

49. 

3 

52.6 

3 

56. 

4 

60.8 

4 

65. 

4 

65.4 

4 

70. 

4 

74.8 

5 

75.10 

'    5 

81.3 

5 

81.8 

5 

87.6 

5 

93.4 

6 

91. 

i    6 

97.6 

6 

98. 

6 

105. 

6 

112. 

7 

106.2 

I    7    113.9 

7 

114.4 

7 

122.6 

7 

130.8 

8 

121.4 

!    8    130. 

8 

130.8 

8 

140. 

8 

149.4 

9 

136.6 

i    9    146.3 

9 

147. 

9 

157.6 

9 

168. 

10 

151.8 

10  1  162.6 

10 

163.4 

10 

175. 

10 

186.8 

11 

166.10 

ill 

178.9 

11 

179.8 

11 

192.6 

11 

205.4 

12 

182. 

12 

195. 

12 

196. 

12 

210. 

12 

224. 

13 

197.2 

!13 

211.3 

13 

212.4 

13 

227.6 

13 

.242.8 

14 

212.4 

14 

227.6 

14 

228.8 

14 

245. 

14  !'  261.4 

15 

227.6 

15 

243.9 

15 

245. 

15 

262.6 

15  ;  280. 

16 

242.8 

16 

260. 

16 

261.4 

16 

280. 

16  \  298.8 

17 

257.10 

17 

276.3 

17 

277.8 

17 

297.6 

17    317.4 

18  I  273. 

18 

292.6 

18 

294. 

18 

315. 

18    336. 

19  I  288.2 

19 

308.9 

19 

310.4 

19 

332.6 

19    354.8 

20    303.4 

20 

325. 

20 

326.8 

20 

350. 

20    373.4 

GLOSSARY  OF  TERMS 

IN    COMMON    USE    AMONG    CAKPENTERS. 


159 


GLOSSARY. 


A. 

ADHESION.  A  physical  term, 
denoting  the  force  with  which  a 
body  remains  attached  to  another 
when  brought  in  contact.  Cohe- 
sion is  the  force  that  unites  the 
particles  of  a  homogeneous  body. 
The  insertion  of  a  nail  into  wood 
is  accomplished  by  separating  the 
particles,  and  thereby  destroying 
the  cohesion;  and  its  extraction, 
by  overcoming  the  adhesion  and 
friction.  Adhesion,  as  related  to 
woods,  may  be  considered  as  fol- 
lows :  3^.  nails,  18  of  which  weigh 
1  pound,  1£  in.  long,  when  driven 
£  in.  into  spruce,  across  the  fibres 
of  the  wood,  require  a  force  of  73 
pounds  to  extract  them.  A  Qd. 
nail,  driven  1  in.  into  dry  oak, 
resists  a  strain  of  507  pounds ;  and 
when  into  dry  elm,  378  pounds.  I 
If  the  same  nail  be  driven  into  ; 
elm  endwise,  or  parallel  with  the 
grain,  it  may  be  drawn  out  by  a 
strain  of  2of  pounds.  The  adhe- 
sion, therefore,  when  driven  into 
the  wood  named,  across  the  grain, 
or  at  right  angles  to  the  fibres,  is 
greater  than  when  driven  parallel 
with  them,  as  4  to  3.  In  dry 
spruce,  it  is  nearlv  as  2  to  1.  A 
common  screw,  a  fifth  of  an  inch  in 
diameter,  has  an  adhesion  about 
three  times  as  great  as  a  common 
Gd.  nail.  If  the  nail  last  named 
be  driven  2  in.  into  dry  oak,  it  will  ! 
resist  a  direct  strain  of  nearly  half 
a  ton. 


ADZE.  An  edged  tool  used  by 
carpenters  to  chip  surfaces  lying 
in  a  horizontal  position,  or  in 
situations  where  they  cannot  easi- 
ly be  cut  with  an  axe. 

ANGLE.  A  term  in  geometry 
signifying  a  corner,  or  the  point 
where  two  converging  lines  meet. 
Angles  are  of  three  kinds;  viz., 
riV/it,  obtuse,  and  acute.  A  right 
angle  is  formed  by  a  line  joining 
another  perpendicularly,  or  at  an 
inclination  of  90°,  which  is  one 
quarter  of  a  circle.  In  an  obtuse 
angle,  the  inclination  of  the  lines 
is  greater  or  more  open  than  90°. 
In  acute  angles,  their  inclination 
is  less  than  a  right  angle.  A  solid 
angle  is  the  meeting  of  three  or 
more  plain  angles  at  a  point. 

ANGLE-BRACE.  A  piece  framed 
across  the  angle  of  a  piece  of  fram- 
ing. It  is  also  termed  an  ang-le- 
tie,  or  diagonal  tie,  and  is  nearly 
synonymous  with  brace. 

ANGLE-RAFTER.  A  piece  in 
a  hip-roof  at  the  line  where  the 
two  adjacent  inclined  sides  unite. 
It  is  continued  from  the  eaves  to 
the  ridge,  and  serves  to  support  the 
jack-rafters. 

APERTURE.  An  opening 
through  a  wall  or  partition. 
u  Apertures,"  says  Sir  Henry 
Wotton,  "are  inlets  for  air  and 
light:  they  should  be  as  few  in 
number,  and  as  moderate  in  di- 
mensions, as  may  possibly  consist 
with  other  due  respects ;  for.  in  a 
word,  all  openings  are  weakenings. 


160 


GLOSSARY. 


They  should  not  approach  too 
near  the  angles  of  the  walls ;  for 
it  were,  indeed,  a  most  essential 
solecism  to  weaken  that  part  which 
must  strengthen  all  the  rest." 

APRON.  The  horizontal  piece 
in  wooden  stairs  supporting  the 
carriages  at  their  landings. 

ARC.  A  term  in  geometry  sig- 
nifying any  portion  of  a  circle,  or 
curve. 

ARRIS.  The  intersecting  line 
where  two  surfaces  of  a  body 
meet. 

ARRIS-FILLET.  A  piece  of 
wood,  triangular  in  section,  used 
to  raise  the  slates  or  shingles 
which  are  against  any  portion  of 
the  work  projecting  from  the  roof; 
as  a  party-wall,  sky -light,  chim- 
ney, battlement.  &c. 

ARTIFICER. '  One  skilled  in 
any  mechanical  art ;  an  inventor, 
or  contriver. 

ARTISAN .  A  mechanic  trained 
to  manual  dexterity  in  any  art  or 
trade. 

ASHLERING.  The  short  studs 
of  a  building  between  the  plate 
and  girt  of  the  attic-floor.  Build- 
ings are  framed  in  this  manner 
where  the  attic  is  designed  for  oc- 
cupation ;  the  short  studs  cutting 
off  the  acute  angle  which  the 
rafters  would  make,  were  they 
permitted  to  come  to  the  floor. 

AUGER.  A  tool  used  by  car- 
penters for  boring  holes. 

AUXILIARY  RAFTERS.  Pieces 
of  timber  framed  in  the  same  ver- 
tical plane  with  principal  rafters, 
placed  under  and  parallel  to  them  I 
to  give  additional  strength  to  the  I 
truss.     (See  Plate  XI.) 

AXE.     An  instrument  for  hew-  ' 
ing  timber  or  chopping  wood.    The 
axe  is  of  two  kinds ;  the  broad  axe 
for  hewing  (the  handle  of  which  j 
is  usually  so  bent  as  to  adapt  it  j 
for  hewing  either  right  or   left), 
and  the  narrow  axe  for  cutting, 
&c. 

AXIS  OF  A  DOME.  A  right 
line  passing  through  its  centre, 
and  perpendicular  to  its  base. 


B. 

BACK.  The  side  opposite  the 
face  of  any  piece  of  work.  When 
a  timber  is  in  a  horizontal  or  in- 
clined position,  the  upper  side  is 
called  the  back;  and  the  under 
side,  the  breast.  The  top  side  or 
surface  of  rafters,  and  the  curved 
ribs  of  ceilings  or  of  hand-rails, 
are  called  backs. 

BACKING  A  HIP-RAFTER, 
OR  RIB.  The  act  of  forming  the 
upper  surface  of  either  in  such  a 
manner  as  to  make  it  range  with 
the  backs  of  the  rafters,  or  ribs, 
on  each  side. 

BALKS,  or  BAULKS.  Small 
sticks  of  roughly  hewn  timber, 
being  the  trunks  of  small  trees 
partially  squared.  The  term  usu- 
ally denotes  sticks  less  than  10 
in.  square  at  the  but,  and  taper- 
ing a  good  deal  as  they  approach 
the  other  end. 

BAR-POSTS.  Posts  fixed  in 
the  ground  at  the  sides  of  a  field- 
gate.  They  are  mortised  to  re- 
ceive the  movable,  horizontal  bars. 

BASIL.  The  slope  or  angle  of 
an  edge  tool,  as  that  on  a  chisel 
or  plane-iron.  The  angle  is  usu- 
ally 12°  for  soft  and  18P  for  hard 
wood. 

BATTER.  A  term  applied  to  a 
wall  which  is  not  plumb  or  per- 
pendicular on  its  face,  but  which 
slopes  from  an  observer  standing 
in  front. 

BAULK-ROOFING.  A  term  in 
use  when  timbers  were  generally 
hewn,  instead  of  sawn  as  at  pre- 
sent. It  formerly  designated  a 
roof  framed  of  baulk-timber, 
which,  being  hewn  from  small 
trees,  could  not  be  formed  into 
square  timbers,  having  an  arris 
full  and  square. 

BAY.  The  space  intervening 
between  two  given  portions  of  the 
wall  or  floors  of  a  building. 

BAY  OF  JOISTS.  The  joist- 
ing  of  a  particular  portion  of  a 
building,  as  between  the  posts 
of  a  side-wall  or  the  girders  of  a 
floor. 

BEAM.  A  large  and  long  piece 
of  squared  timber,  used  in  hori- 


GLOSSARY. 


161 


zontal  positions  for  supporting  a 
superincumbent  weight,  or  for 
counteracting  two  opposite  forces, 
tending  either  to  stretch  or  to 
compress  it  in  the  direction  of  its 
length.  Employed  as  a  lintel,  or 
for  the  support  of  the  ends  of 
joists  in  a  floor,  it  simply  sustains 
a  weight ;  if  employed  as  a  tie- 
beam  to  the  truss  of  a  roof,  it  re- 
sists the  strain  or  thrust  exerted 
by  the  truss-rafters;  or,  if  as  a 
collar-beam  between  the  heads  of 
truss-rafters,  it  resists  the  strain 
they  exert,  and  is  compressed. 

BEAM-COMPASS.  An  instru- 
ment for  describing  circles  of  a 
larger  diameter  than  may  be  prac- 
ticable with  ordinary  compasses. 
It  consists  of  a  rod,  or  beam,  on 
which  are  two  sliding  sockets,  one 
provided  with  a  sharp  steel  needle 
for  fixing  the  centre  of  the  cir- 
cle to  be  described,  and  the  other 
with  a  pencil  for  describing  the 
circle  itself.  A  very  common 
method  among  carpenters  for 
marking  large  circles,  such  as 
plans  of  domes,  &c.,  is  to  de- 
termine the  centre,  and  then  affix 
to  it  the  end  of  a  slip  or  lath  of 
•wood,  at  the  other  extremity  of 
which  is  the  instrument  for  tra- 
cing the  circle  required. 

BEAM-FILLING.  The  brick- 
work about  the  rafters  at  the 
eaves  of  a  brick  building. 

BEAKER.  Any  timber  or  wall 
that  supports  another  timber,  and 
retains  it  in  its  proper  place. 

BEARING.  The  distance  or 
length  which  the  ends  of  a  timber 
or  joist  rest  on  another,  or  are 
inserted  in  a  wall.  A  beam  in- 
serted 12  in.  in  a  pier  or  wall  is 
said  to  have  a  12  in.  bearing. 

BEETLE.  A  large  and  heavy 
wooden  mallet  or  hammer  for 
driving  stakes,  piles,  wedges,  &c. 
It  has  one,  two,  or  three  handles, 
as  may  be  required. 

BELFRY.  The  part  or  section 
of  a  steeple  in  which  the  bell  is 
suspended.  The  term  was  for- 
merly used  to  denote  more  parti- 
cularly the  framing  to  which  the 
bell  was  hung. 

BELL-ROOF.    A  roof  the  ver- 


tical section  of  which  is  concave 
at  the  bottom,  and  convex  at  the 
top.  It  is  often  called  an  ogee 
roof. 

BELVIDERE.  A  turret  or  lan- 
tern used  for  an  observatory ;  also 
an  arbor  or  artificial  eminence  in 
a  garden. 

BEVEL.  An  instrument  of  the 
nature  of  a  try-square,  one  leg 
being  movable  on  a  centre,  so 
that  it  may  be  set  at  any  angle. 
The  term  also  denotes  an  angle 
which  is  more  or  less  than  a  right 
angle. 

BINDING-JOISTS.  In  old  me- 
thods of  framing,  binding-joists 
were  large  joists  or  timbers  framed 
between  the  girders,  in  a  trans- 
verse direction,  for  the  support 
of  the  floor-joists  above,  and  the 
ceiling-joists  below.  Thus  method 
of  framing  is  now  but  seldom 
used  in  this  country. 

BOARD.  In  America,  a  board 
is  a  piece  of  timber  of  any  length 
or  width,  and  from  £  in.  to  2  in. 
in  thickness.  Pieces  of  2  or  more 
in.  up  to  6  in.  in  thickness  are 
called  planks.  In  England,  a 
board  is  a  piece  of  timber  more 
than  4  in.  in  width,  and  may  be 
2J  in.  thick ;  and  all  boards  wider 
than  9  in.  are  called  planks. 

BOARDING-JOISTS.  The  same 
as  floor- joists. 

BOLT.  A  square  or  round  iron 
pin,  with  a  head  or  flange  at  one 
end,  and  a  thread  and  nut  at  the 
other. 

BOND.  Any  thing  that  con- 
nects and  retains  two  or  more 
bodies  in  a  particular  position. 

BOND-TIMBERS.  The  tim- 
bers or  pieces  of  wood  which  are 
built  into  the  walls  of  a  brick 
or  stone  building  to  secure  the 
internal  finishing. 

BONING.  The  act  of  judging 
and  forming  a  plain  surface  or 
straight  line  by  the  eye.  The  art 
is  usually  termed  sighting.  Car- 
penters and  joiners  use  for  this 
purpose  two  straight  edges,  by 
which  they  determine  whether  the 
surface  is  true  or  twisted 

BORING.  The  act  of  perforat- 
ing any  substance.  In  joinery, 


11 


162 


GLOSSARY. 


this  is  done  with  a  hrad-awl,  gim- 
let, or  bit ;  and  in  carpentry,  by  an 
auger. 

BOW.  Any  part  of  a  building 
that  projects  from  a  straight  wall. 
It  may  be  either  circular  or  po- 
lygonal in  plan:  the  last-named 
are  termed  canted  bows. 

BRACE.  A  piece  of  timber 
fixed  across  the  internal  angle  of 
the  larger  timbers  of  a  frame ;  by 
which  arrangement  the  whole  of 
the  work  is  stiffened,  and  the 
building  prevented  from  swerving 
either  way. 

BREAK  IN.  An  old  expression 
in  use  among  carpenters,  signify- 
ing the  act  of  cutting  or  breaking 
a  hole  into  a  brick  or  stone  wall 
to  admit  the  ends  of  joists,  beams, 
&c. 

BREAST-SUMMER.  A  piece  of 
timber  used  for  sustaining  a  su- 
perincumbent weight,  and  per- 
forming the  office  of  a  lintel  over 
any  large  opening ;  as  large  win- 
dows, or  doors  in  a  store,  or  an 
open  passage-way  under  the  se- 
cond story  of  a  building. 

BBIDGE.  A  term  denoting  that 
one  timber  lies  across  and  im- 
mediately upon  another,  or  is 
notched  into  it.  Thus,  in  framed 
roofing,  the  common  rafters  bridge 
over  the  purlins,  and  the  purlins 
over  the  principal  rafters. 

BRIDGING.  Pieces  placed  be- 
tween timbers  to  prevent  their 
nearer  approach.  In  floors,  the 
joists  are  often  stayed  in  this 
manner  by  pieces  of  the  same 
kind  of  joist  cut  and  nailed  in 
between  them  at  right  angles,  or 
by  narrow  pieces  of  board  placed 
in  a  similar  position,  and  diago- 
nally crossing  each  other. 

BRIDGING-FLOORS.  Those 
in  whose  construction  bridging- 
joists  are  used. 

BRIDGING-JOISTS.  Those  sus- 
tained by  a  beam  beneath  them. 

BUILDING.  A  fabric  or  edifice 
of  any  kind,  constructed  for  occu- 
pancy ;  as  a  house,  barn,  church, 
&c. 

BULKER.  A  term  in  use  in 
some  parts  of  England  to  denote 
a  beam  or  rafter. 


BUTMENT-CHEEKS.  The  two 
sides  of  a  mortise  in  any  piece  of 
framing. 

BUT- END.  The  end  nearest 
the  root  of  a  tree. 

BUTTRESS.  A  pier  or  external 
support,  designed  to  resist  any 
pressure  from  within  which  may  af- 
fect the  wall  or  thing  so  supported. 


o. 

CALIBER.  The  greatest  dia- 
meter of  any  round  body ;  as  of  a 
log  or  ball,  or  the  bore  of  a  gun. 

CAMBER.  An  arch  or  curve 
on  the  top  of  an  aperture  or  of  a 
beam.  A  beam  is  said  to  be  cam- 
bered when  it  is  hewn  or  bent  so 
as  to  form  a  slight  curve. 

CAMBER-BEAMS.  Beams 
which  are  cambered. 

CAMBERATED.  Archedor 
vaulted. 

CAMPANILE.  Atovrerfor 
bells.  In  Italy  they  are  usually 
separate  from  the  church,  and  are, 
in  general,  highly  ornamented  and 
costly  edifices.  The  celebrated 
one  at  Cremona  is  395  ft.  high. 
That  at  Florence,  built  from  a  de- 
sign by  Giotto,  is  267  ft.  high, 
and  45  ft.  square.  The  most  re- 
markable campanile  in  the  world 
is  doubtless  that  at  Pisa :  it  was 
built  about  the  year  1174,  and  is 
commonly  known  as  the  "  Leaning 
Tower."  It  is  cylindric  in  plan; 
is  50  ft.  in  diameter,  and  150  ft. 
to  the  platform,  on  which  are  the 
bells.  From  this  platform  a 
plumb-line  falls,  on  the  leaning 
side,  nearly  13  ft.  from  its  base. 
Its  entire  height  is  180  feet. 

CAMPSHOT.  The  sill  or  cap 
of  a  wharf  or  wall. 

CANT.  An  external  corner  or 
angle  of  a  building.  Among  car- 
penters, the  term  is  also  used  to 
denote  the  act  of  turning  a  piece 
of  timber. 

CANTHERS.  In  ancient  car- 
pentry, the  ends  of  the  jack- 
rafters  of  a  roof.  They  are  con- 
sidered by  some  to  have  given 
rise  to  the  mutules  of  the 
order. 


GLOSSARY. 


163 


CAPSTAN.  A  strong  and  massy 
column  or  cylinder  of  iron  or 
wood,  at  the  top  of  which  is  a  cir- 
cular cap,  with  horizontal  mortise? 
or  holes  around  it  at  equal  dis- 
tances to  receive  bars  or  levers,  for 
the  purpose  of  turning  it,  and 
thus  winding  up  a  rope,  the  other  i 
end  of  which  is  attached  to  the 
weight  to  be  raised,  or  to  apply 
the  power  of  the  machine  to  any 
thing  requiring  removal. 

CARCASS.     The   unfinished 
state  of  a  building  before  it  is  par-  j 
titioned  off  into  rooms,  the  floors 
laid,  &c. 

CARPENTER.  In  America  this 
word  is  often  used  indiscrimi- 
nately to  signify  an  artificer  who 
begins  and  completes  the  entire 
wood-work  of  an  edifice.  The  | 
term  properly  denotes  one  who 
does  the  framing,  raising,  board- 
ing, and  partitioning  off  the 
rooms  of  a  wooden  building.  The 
finishing  of  its  several  parts  is 
done  by  the  joiner.  In  ship- 
building the  carpenter  hews  out 
the  timbers,  sets  up  the  frame, 
and  planks  it;  while  the  ship- 
joiner  completes  the  work. 

CARPENTER'S  RULE.  An  in- 
strument by  the  use  of  which 
carpenters  take  dimensions,  &c. 
It  is  figured  in  inches,  and  parts 
of  inches ;  and  to  some  kinds  is 
affixed  a  slide,  the  figures  upon 
which  enable  the  artificer  to  make 
calculations  in  multiplication  and 
division,  besides  many  others 
which  constantly  occur  in  his 
practice. 

CARPENTER'S  SQUARE.    An 
instrument  made  of  steel,  one  leg 
of  which  is  24  in.  long  and  2  in. 
wide,  and  the  other  16  in.  long 
and  H  in.  wide;   the  legs  being  ; 
figured  in   inches,  and  parts   of  i 
inches.     This  instrument  is  used  | 
not  only  as  a  square  and  measur-  ] 
ing-rule,  but,  with  a  plummet  and  j 
line,   to  determine  levels.       The 
joiner's   square   has    one    leg  of  | 
wood,  and  the  other  of  steel  with-  ] 
out  figures. 

CARPENTRY.  The  work  per- 
formed  by  carpenters,  or  the  art 
of  hewing,  framing,  and  joining  ' 


the  timbers,  and  ah1  the  heavier 
parts  of  a  building.  Also  a  struc- 
ture of  framed  timbers  ;  as  a 
roof,  a  floor,  or  an  arch-center- 
ing. 

CARRIAGE.  The  diagonally 
notched  plank  which  is  placed  in 
an  oblique  position  for  the  sup- 
port of  the  treads  and  risers  of  a 
flight  of  stairs. 

CASSION.  A  large  and  strong 
chest,  made  water-tight,  and  used 
in  the  construction  of  the  piers 
of  a  bridge,  where  the  rapidity 
and  depth  of  the  river  present  a, 
difficulty  in  building  the  founda- 
tion. The  floor  of  a  cassion  is  so 
constructed  that  the  sides  may  be 
detached  from  it  when  desired. 
The  bed  of  the  river  is  levelled  at 
the  site  of  the  proposed  pier;  the 
cassion  is  launched,  and  floated 
to  the  location,  and  sunk.  The 
pier  is  then  built  therein  as  high 
as  the  level  of  the  water;  the 
sides  of  the  cassion  are  then  re- 
moved, the  pier  resting  on  the 
foundation  prepared  for  it.  The 
tonnage  of  each  of  the  cassions 
used  in  the  construction  of  West- 
minster Bridge,  over  the  Thames, 
was  equal  to  that  of  a  forty -gun 
ship. 

CASTING.  A  term  denoting 
the  bending  or  twisting  of  a  board 
or  any  piece  of  wood  from  its  ori- 
ginal state.  It  is  synonymous 
with  warping: 

CATENARY  CURVE.  The 
curve  formed  by  a  chain  or  rope, 
of  uniform  density,  hanging  freely 
between  two  points  of  suspension. 
Galileo  is  supposed  to  have  been 
its  discoverer:  and  it  is  certain 
that  he  proposed  it  as  the  proper 
figure  for  an  arch  of  equilibrium ; 
supposing  it,  however,  to  be  iden- 
tical with  the  parabola.  James 
Bernonilli,  an  eminent  mathe- 
matician, born  at  Basil  in  1654, 
investigated  its  nature ;  but  its  pe- 
culiar properties  were  afterwards 
demonstrated  by  John  Bernouilli, 
his  brother.  Their  opinion  was 
adopted  and  advocated  by  Iluy- 
gens  and  Leibnitz. 

CEILING.  The  surface  of  a 
room  opposite  the  floor. 


164 


GLOSSARY. 


CENTRE.  A  point  which  is 
equally  distant  from  the  extre- 
mities of  a  line,  figure,  or  body : 
the  middle  point  or  place  of  any 
thing. 

CENTERING.  The  temporary 
frame  or  woodwork  whereon  any 
arched  work  is  constructed. 

CHALK.  A  variety  of  carbon- 
ate of  lime.  Red  chalk  is  an 
indurated  or  hardened  ochre,  and 
takes  its  name  from  its  color. 
French  chalk,  used  by  tailors,  is 
a  soft  magnesian  mineral,  of  the 
nature  of  steatite,  or  soapstone. 

CHAMFER.  A  furrow,  slope, 
or  bevel.  A  beam  or  joist  is  said 
to  be  chamfered  when  the  arris 
is  so  cut  as  to  convert  its  original 
right  angle  into  an  obtuse  angle, 
at  the  lines  where  the  slope  inter- 
sects with  the  plane  of  the  other 
sides. 

CHEEKS.  Two  upright,  simi- 
lar, and  corresponding  parts  of 
any  timber-work  ;  such  as  the 
studs  at  the  sides  of  a  door,  win- 
dow. &c. 

CHIP.  A  piece  of  wood,  or 
other  substance,  separated  from  a 
body  by  any  cutting  instrument. 
As  a  verb,  it  signifies  to  separate 
into  small  pieces  or  chips  by  gra- 
dually hewing  or  cutting. 

CHISEL.  A  well-known  instru- 
ment, made  of  iron,  faced  at  the 
bevel,  or  cutting  end,  with  steel. 
Those  used  for  paring,  being  thin, 
are  called  paring-chisels  :  those 
used  for  framing  are  heavier  and 
thicker,  being  called  firmer  or 
framing  chisels. 

CHIT.  An  instrument  formerly 
used  for  cleaving  laths. 

CHORD.  The  right  line  which 
joins  the  two  extremities  of  an 
arc.  It  is  so  called  from  its  re- 
semblance to  a  bow  and  string, 
the  chord  representing  the  string. 

CIRCLE.  A  figure  bounded  by 
one  continued  curved  line,  called 
the  circumference,  all  parts  of 
which  are  equidistant  from  a 
point  called  the  centre.  It  is  the 
most  capacious  of  all  plain  figures. 
The  circumference  of  any  circle, 
divided  by  3.1416,  will  give  the 
diameter;  or  the  diameter,  multi- 


plied by  the  same  number,  will 
give  the  circumference.  In  com- 
mon practice,  where  great  exact- 
ness is  not  required,  it  is  usual  to 
consider  the  diameter  to  the  cir- 
cumference as  22  to  7. 

To  find  the  area  of  any  circle, 
multiply  half  the  diameter  by 
half  the  circumference ;  or,  for  a 
more  accurate  calculation,  inul- 
ti  ply  the  square  of  the  diameter 
by  .7854,  or  the  square  of  the 
circumference  by  .07958.  Squar- 
ing the  circle,  as  it  is  termed,  is 
the  attempt  to  ascertain  the  exact 
contents  of  a  circle  in  square 
measure,  —  a  problem  as  yet  un- 
solved. 

CLAMP.  A  piece  of  wood  so 
fixed  to  another  that  the  fibres 
or  grain  of  one  may  cross  those 
of  the  other,  and  thus  prevent  its- 
warping  or  twisting. 

CLEAR.  The  clear  or  unmo- 
lested distance  between  any  two 
surfaces  or  points.  The  net  dis- 
tance between  a  floor  and  ceiling 
is  said  to  be  the  height  of  the 
story  in  the  clear. 

CLERE-STORY.  A  con- 
tinuation of  the  nave,  choir,  and 
transepts  of  a  church,  above  the 
roof  of  the  aisles. 

CLEAVING.  The  act  of  sepa- 
rating, by  force,  one  part  of  a 
piece  of  wood  or  other  substance 
from  another,  in  the  direction  of 
its  fibres. 

CLEFTS.  Those  cracks  or  fis- 
sures produced  in  wood  when 
wrought  too  green ;  or  when,  in 
an  unseasoned  state,  it  is  exposed 
to  sudden  heat.  In  thin  stuff,  as 
boards,  &c.,  the  clefts,  being  some- 
what different  from  those  in  fram- 
ing lumber,  are  usually  termed 
sh  akes. 

COCKING.  A  method  of  con- 
fining the  tie-beams  of  a  roof  to 
the  top  of  the  wall-plates,  or  the 
joists  of  a  floor  to  the  girders  and 
girts,  by  dove-tailing  the  parts 
together.  Its  design  is  to  prevent 
the  walls  from  spreading. 

COLLAR-BEAM.  A  beam  used 
to  prevent  the  bending  or  sagging 
of  the  rafters  in  a  common  roof, 
or  the  nearer  approach  of  the  tops 


GLOSSARY. 


165 


of    the    rafters    in   one  that    is 
trussed. 

COMPASSES.  A  mathematical 
instrument  for  describing  circles 
and  measuring  distances.  Com- 
mon compasses  need  no  descrip- 
tion. Triangular  compasses  have, 
in  addition  to  the  two  legs  of  com- 
mon ones,  another,  made  with  a 
joint,  and  movable  in  any  direc- 
tion. >  Beam  compasses  are  de- 
signed for  describing  large  circles. 
(See  description.)  Proportional  i 
compasses  have  two  pairs  of  legs,  j 
connected  by  a  shifting  centre 
sliding  in  a  groove,  and  thereby 
regulating  the  proportion  which 
the  opening  or  distance  between 
the  joints  at  one  end  bears  to  that 
at  the  other.  They  are  used  to 
enlarge  or  diminish  drawings  to 
any  given  scale. 

COMPRESSIBILITY.  The  qua- 
lity of  being  compressible,  or  the 
capacity  of  being  reduced  to 
smaller  dimensions.  A  post  sus- 
taining a  heavy  superincumbent 
weight,  or  the  collar-beam  or 
strut  of  a  truss-roof,  when  in  use, 
are  said  to  be  in  a  state  of  com- 
pression. 

CONCU3.  This  term  is  doubtless 
derived  from  the  Latin  concutio, 
to  shake  or  shatter.  In  carpen- 
try, it  properly  denotes  wood  so 
rotten  or  decayed  in  some  of  its 
parts  as  to  be  shaky.  Of  late 
years,  it  is  generally  used  to  signify 
rotten  or  decayed  knots;  and 
boards  or  sticks  of  timber  having 
such  knots  are  termed  concussed. 

COXE.  A  solid  body  having  a 
circle  for  its  base,  and  terminating 
at  its  top  in  a  point,  or  vertex. 

CONICAL  ROOF.  A  roof  whose 
exterior  surface  is  formed  like  a 
cone. 

CONSTRUCTION.  The  act  of 
building,  or  of  devising  and  form- 
ing. Among  architects,  the  term 
more  generally  denotes  the  ar- 
ranging and  distributing  of  the 
parts  of  a  building  in  such,  a  man- 
ner as  will  insure  durability  to 
the  structure,  and  economy  in  the 
use  of  its  materials. 

CONSTRUCTITE  CARPENTRY. 
Practical  or  operative  carpentry. 


CONTACT.  A  touching  or 
juncture  of  two  bodies.  Tnings 
are  said  to  be  in  contact  when 
parts  of  them  are  so  near  together 
that  there  is  no  sensible  interven- 
ing space.  The  places  where  they 
touch  are  called  the  points  of  con- 
tact. 

CONTOUR.  The  outline  bound- 
ing any  figure. 

CONTRACTION.  The  act  of 
drawing  together  or  shortening, 
by  causing  the  parts  of  a  body  to 
approach  each  other.  Thus,  in  an 
iron  rod,  heat,  by  insinuating  it- 
self between  the  particles  of  the 
metal,  causes  the  rod  to  become 
longer ;  and  it  is  then  said  to  be 
expanded.  Cold,  which  is  simply 
the  absence  of  heat,  causes  or  per- 
mits the  particles  to  come  nearer 
each  other ;  and  the  rod  in  this 
state  is  said  to  be  contracted. 

CONVERGENT  LINES.  Lines 
tending  te  one  point,  and  which, 
if  continued,  would  meet. 

COUNTER-SINK.  To  sink  a 
recess  or  cavity  in  any  material, 
for  the  reception  of  a  projection  on 
the  piece  to  be  connected  with  it; 
as  the  head  of  a  screw  or  bolt,  or 
the  plate  of  iron  against  which 
the  nut  or  head  of  a  bolt  is  fixed. 

CRADLING.  The  timber-ribs 
to  which  are  nailed  the  laths  or 
furrings  of  a  vaulted  ceiling. 

CRAMP.  An  iron  instrument 
used  by  carpenters  to  draw  or 
force  mortises  and  tenons  toge- 
ther. It  is  made  of  iron,  with  a 
movable  shoulder  at  one  end,  and 
a  screw  at  the  other. 

The  term  also  denotes  a  piece 
of  iron  bent  at  the  ends  towards 
one  side,  and  used  to  confine  the 
larger  timbers  of  a  frame  toge- 
ther. 

CRANE.  A  machine  for  raising 
great  weights.  It  consists  of  a 
stout  upright  shaft  or  post,  termed 
a  puncheon,  from  which  projects  a 
strong  arm,  or  piece  of  timber, 
furnished  at  the  extremity  with  a 
tackle  and  pulley. 

CROSS-BEAM.  A  large  beam 
extending  from  wall  to  wall  of  a 
building,  or  the  girder  holding 
the  sides  of  an  edifice  together. 


166 


GLOSSARY. 


CROSS-GRAINED.  A  twisted 
or  irregular  disposition  of  the 
fibres  of  wood,  as  in  that  part  of 
a  tree  where  the  branches  shoot 
from  the  trunk*. 

CROSS-SPRINGERS.  Ina 
groined  ceiling,  the  ribs  springing 
from  the  diagonals  of  the  piers  or 
pillars  on  which  an  arch  rests. 

CROWN  OF  AN  ARCH.  Its 
highest  point  of  elevation. 

CUBIT.  A  lineal  measure,  of 
different  length  in  different  na- 
tions. In  ancient  architecture,  it 
was  equal  to  the  length  of  the 
arm  from  the  elbow  to  the  extre- 
mity of  the  middle  finger,  or  about 
18  in.  According  to  Dr.  Arbuth- 
not,  the  Roman  cubit  was  17  4-10 
in. ;  and  the  Scripture  cubit,  a 
little  less  than  22  in.  The  geo- 
metrical cubit  of  Vitruvius  was  6 
ordinary  cubits,  or  9  ft. 

CURB-ROOF.  A  roof  having 
two  different  slopes  on  each  side. 
It  is  identical  with  the  gambrel- 
roof. 

CURB-PLATE.  A  circular 
plate  or  curb,  formed  by  scarfing 
two  or  more  curved  pieces  toge- 
ther at  their  ends,  or  by  uniting 
together  pieces  of  plank  in  layers, 
breaking  the  joints  as  in  brick- 
work. Curb-plates  are  used  at  the 
eye  of  domes,  &c. 

CURLING-STUFF.  Wood  in 
•which  the  fibres,  instead  of  being 
straight,  are  winding,  as  where 
the  branches  of  trees  shoot  from 
the  trunk ;  the  spiral  character 
of  the  formation  causing  the  wood 
to  wind  or  curl. 

CURSOR.  The  sliding  part  of 
beam-compasses,  or  that  part  of 
proportional  compasses  by  which 
the  points  are  set  at  a  given  ratio. 

CURVE.  A  line  that  is  neither 
straight  nor  composed  of  straight 
lines,  but  which  bends  continually 
without  angles. 

CURVILINEAR.  Bounded  by 
a  curved  line.  Thus  a  roof  is 
curvilinear  when  its  plan  is  either 
circular  or  elliptical. 

CUT-ROOF.  One  that  is  trun- 
cated, having  a  flat  on  the  top. 


D. 

DAM.  A  mole,  bank,  or  wall 
of  earth,  or  a  frame  of  wood,  built 
to  obstruct  a  current  of  water, 
and  raise  its  level  for  driving  ma- 
chinery, &c. 

DEAL.  A  term  more  commonly 
used  in  England  than  in  America. 
It  denotes  the  wood  of  the  fir- 
tree,  when  made  into  pla&ks  or 
boards.  They  are  imported  into 
England  from  Christiana  and 
Dantzic,  taking  the  names  of  Chris- 
tiana deals  and  Dantzic  deals.  The 
usual  thickness  of  the  former  is  3 
in.,  and  their  width  9  in.  Those 
of  1$  in.  thickness  are  called 
whole  deals;  and  those  of  half 
that  thickness,  slit  deals. 

DENSITY.  A  term  in  physics, 
denoting  the  closeness  or  compact- 
ness of  the  constituent  parts  of  a 
body.  In  philosophy,  the  density 
of  a  body  is  the  quantity  of  mat- 
ter contained  in  a  given  bulk. 
Thus,  if  a  body  of  equal  bulk  or 
size  with  another  is  of  double 
the  density,  it  contains  double  the 
quantity  of  matter.  For  example: 
A  cubic  foot  of  oak  is  more  dense, 
and  therefore  contains  more  mat- 
ter, than  the  same  amount  of  pine ; 
and  a  cubic  foot  of  iron,  being 
more  dense,  contains  more  matter 
than  either.  The  weight  required 
to  crush  a  piece  of  wood  is  rela- 
tively as  the  density  of  the  wood. 
A  block  of  pine,  being  less  dense 
than  one  of  oak,  is  therefore  more 
easily  crushed. 

DERRICK.  A  machine  used  by 
carpenters  for  raising  any  heavy 
body ;  as  the  larger  timbers  of  a 
frame,  or  sections  of  the  frame 
itself. 

DESIGN.  In  architecture,  a 
term  denoting  a  plan  or  represen- 
tation of  any  building.  The  term 
signifies  either  the  general  ar- 
rangement of  floors,  or  the  ar- 
rangement and  disposition  of  the 
windows,  doors,  &c.,  of  a  build- 
ing. 

DETAILS.  Drawings  made  on  a 
larger  scale  than  those  which  sim- 
ply exhibit  the  design  of  a  build- 
ing. They  are  usually  of  the  full 


GLOSSARY. 


167 


size  of  the  work  to  be  executed,  : 
and  are  often  termed  working-  i 
drawings. 

DIAGONAL.      A  right  line  so 
drawn  through  a  figure  as  to  join 
the  two  opposite  angles.    Euclid 
used    the   term    diameter   in    the  | 
same  sense.    In  modern  practice, 
diameter  applies  more  properly  to  i 
circular,  and  diagonal  to  angular  '• 
figures. 

DIAGONAL  SCALE.  A  mea- 
suring scale  fornted  by  horizontal 
lines,  with  diagonals  drawn  across 
them.  It  is  designed  for  particu- 
larly accurate  measurements. 

DIAMETER.  A  right  line  pass- 
ing through  the  centre  of  a  figure, 
and  dividing  it  into  equal  parts. 

DIMENSION.  The  extent  or 
size  of  a  body ;  or  length,  breadth,  i 
and  thickness  or  depth.  A  point  ; 
has  no  dimensions ;  a  line  has  one 
dimension,  —  namely,  length  ;  a 
superfiee  (as  the  side  of  a  squared 
stick  of  timber)  has  two  dimen- 
sions, —  length  and  breadth ;  and  a 
solid  (as  the  whole  stick)  has  three 
dimensions,  —  length,  breadth,  and 
thickness.  The  word  is  generally 
used  in  the  plural,  and  denotes 
the  whole  extent  of,  or  space 
occupied  by,  a  body  ;  as  the 
dimensions  of  a  room,  house,  or 

DISCHARGE.  To  unload  or 
relieve ;  as  the  removal  of  weight 
from  a  beam,  or  other  timber, 
when  too  heavily  loaded. 

DISPOSITION.  The  manner 
in  which  the  several  parts  of  a 
body  are  placed  or  arranged. 

DOME.     The  spherical  or  other 
shaped  convex  roof  over  a  circular 
or    polygonal  building.      A  seg-  \ 
mental  dome  is  one  whose  rise  or 
elevation  is  less  than  one-half  its  ! 
diameter.     A  stilted  or  surmounted  I 
dome  is  higher  than  the  radius  of  '< 
its  plan  or  base.     The  oldest  dome 
of  which  we  are  informed  is  that 
of  the  Pantheon  at  Rome,  which 
was  erected  under  Augustus,  and 
is  still  quite  perfect.     In  the  fol-  ] 
lowing  table  will  be  found  the  di- 
mensions of  several  of  the  princi-  i 
pal  domes  of  Europe.    The  heights 
are  given  from  the  ground. 


ft.d.  ft.h. 

Pantheon  at  Rome   ...  142  143 

Sta.  Maria  del  Fiore  at 

Florence 139  310 

St.  Peter's  at  Rome  ...  139  330 

St.  Sophia  at  Constanti- 
nople    115  201 

Baths  of  Caracalla  (an- 
cient)    112  116 

St.  Paul's,  London  ...  112  215 

Mosque  of  Achmet  ...    92  210 

Chapel  of  Medici  ....    91  199 

Baptistery  at  Florence  .    86  110 

Church  of  Invalids  at 

Paris 80  173 

DORMANT  TREE.  A  word  of 
bad  etymology,  and  nearly  out  of 
use.  It  is  synonymous  with  the 
terms  lintel  and  summer. 

DOUBLE  FLOOR.  A  floor  con- 
structed with  binding  and  bridg- 
ing joists. 

DOVE-TAIL.  A  joint  formed 
like  a  dove's  tail :  hence  its  name. 
It  is  made  by  so  shaping  the  parts 
of  the  wood  to  be  joined,  that, 
when  one  is  let  into  the  other,  it 
cannot  be  drawn  out  by  a  direct 
strain  while  its  wedge-like  form  is 
retained. 

DO  \VELS.  Pins  of  wood  or  iron 
which  unite  two  boards  or  timbers 
in  such  a  manner  as  to  disguise 
the  fastenings. 

DRAFT.  A  drawing  represent- 
ing the  plans,  elevations,  and  sec- 
tions of  a  building,  drawn  to  a 
scale,  thus  exhibiting  all  its  parts 
in  the  same  relative  proportion  to 
each  other  as  they  are  intended 
to  be  in  the  building  itself.  The 
term  "  draught "  signifies  the  same 
thing. 

DRAGON-BEAM.  A  piece  ly- 
ing in  a  horizontal  position,  and 
framed  diagonally  from  each  of 
the  angles  of  a  hip-roof  to  a  piece 
at  right  angles  with  it,  and  which 
is  framed  across  the  corner  from 
one  plate  to  the  other.  The  tim- 
ber into  which  the  dragon-beam  is 
framed  is  called  the  anglr-tie. 

DRAWB011E.  To  confine  a  te- 
non to  a  mortise  by  means  of  a 
pin  through  the  parts,  the  hole  in 
the  tenon  being  nearer  the  shoul- 
der than  the  holes  in  the  cheeks 


168 


GLOSSARY. 


of  the  mortise  are  to  the  abut- 
ment against  which  the  shoulder 
is  to  come. 

DRIFT.  The  horizontal  power 
exerted  by  an  arch  when  it  tends 
to  overset,  or  spread  apart,  the  pier 
from  which  it  springs.  As  a  verb, 
it  denotes  the  act  of  driving  out  a 
pin  or  wedge  by  a  power  exerted 
against  the  smaller  end. 

DRUXEY.  Timber  in  a  state 
of  decay,  having  white,  spongy 
veins,  is  said  to  be  druzey. 

DRY-ROT.  A  disease  in  timber 
which  destroys  the  cohesion  of  its 
parts,  and  reduces  its  substance 
to  a  dry  powder. 

D  \VANGS  (Scotch).  The  short 
pieces  of  board  or  joist  used  in 
bridging  the  joists  of  a  floor. 


EAVES .  The  edge  or  lower  bor- 
der of  a  roof  which  so  projects 
from  the  face  of  a  wall  as  to  throw 
off  the  water  that  falls  on  the 
roof 

EDGE.  The  space  between  the 
lines  of  intersection  of  two  sur- 
faces or  sides  of  a  solid;  being 
that  part  or  superfice  of  a  rectan- 
gular body  which  contains  the 
length  and  thickness ;  and  is  either 
straight  or  curved,  according  to 
the  contour  of  the.  surfaces  or 
sides.  The  edge  of  a  tool  is  the 
part  where  the  two  surfaces  meet 
when  ground  to  an  acute  angle. 

EDIFICE.  A  word  nearly  sy- 
nonymous with  building,  struc- 
ture, or  fabric.  The  term  edifice 
cannot,  however,  be  applied  with 
propriety  to  ordinary  buildings, 
but  rather  denotes  architectu- 
ral structures  of  importance;  as 
large  mansion-houses,  theatres, 
churches,  &c 

EFFECT.  That  quality  in  an 
architectural  composition  which 
is  calculated  to  attract  the  atten- 
tion of  the  beholder,  and  excite  in 
him  the  sensation  intended  by  the 
designer. 

ELASTIC  CURVE.  The  curve 
or  figure  assumed  by  an  elastic 
body,  as  a  lath,  or  thin  strip  of 


•wood  or  whalebone,  when  one 
end  is  fixed  horizontally  in  a  ver- 
tical wall,  and  the  other  loaded 
with  a  weight,  by  which  the  lath 
is  curved  or  bended. 

ELASTICITY.  The  inherent 
property  or  quality  in  a  body  by 
which  it  recovers  its  former  figure 
or  state  after  being  relieved  from 
any  pressure,  tension,  or  distor- 
tion. Elasticity  is  perfect  only 
where  a  body  recovers  its  exact 
original  form  ahd  shape,  and  in 
the  time  which  was  required  to 
produce  the  flexure  or  bending. 
The  quality  of  perfect  elasticity  ia 
rarely,  if  ever,  found.  A  steel  rod 
is  said  to  be  more  elastic  than  one 
of  iron ;  and  a  string  of  India-rub- 
ber is  more  so  than  one  of  hemp 
or  cotton.  Brittle  is  the  opposite 
of  elastic ;  and  therefore  a  piece 
of  wood  is  more  elastic  than  a 
piece  of  glass. 

ELEVATION.  A  drawing  or 
geometrical  representation  of  a 
side  or  end  of  any  building.  In 
an  elevation,  every  part  of  the 
structure  represented  is  supposed 
to  be  directly  opposite  to,  and  on 
a  level  with,  the  eye. 

ELLIPSE.  A  figure  produced 
by  a  plane  passing  obliquely 
through  a  cylinder ;  being  what  is 
commonly  called  an  oval. 

ENTER.  The  act  of  inserting 
the  end  of  a  tenon  into  a  mortise, 
previous  to  its  being  driven  in  up 
to  the  shoulder. 

EXT  R  ADOS.  The  interior 
curve,  or  back,  of  the  stones  or 
voussoirs  of  an  arch. 

EYE  OF  A  DOME.  The  open- 
ing at  its  top  inside  the  curb. 


FABRIC.  Any  large  or  impor- 
tant building. 

FACADE  (French).  A  term 
denoting  the  principal  or  most 
important  front  of  a  building;  as 
that  which  faces  on  a  public 
street,  lawn,  or  garden. 

FATHOM.  A  measure  of  length 
comprising  six  feet.  It  is  used 
chiefly  among  seamen  for  mea- 


GLOSSARY. 


169 


suring  ropes  and  chains,  and  for 
sounding  the  depth  of  water. 

FELLING  TIMBER.  The  act 
of  cutting  down  trees. 

FiLLING-IN  PIECES.  The 
short  studs  which  are  cut  in 
against  the  braces  of  a  frame,  or 
the  short  pieces  of  rafters  cut  in 
against  the  hips  of  a  roof  or 
groin.  The  term  is  synonymous 
with  jack-timber. 

FIRMER-CHISEL.  A  thick 
and  heavy  chisel  for  framing. 
(See  CHISEL.) 

FLANK.  The  part  of  a  build- 
ing that  joins  the  front.  The  side 
of  a  building  is  called  the  flank ; 
and  a  geometrical  elevation  of  the 
same,  a  flank  elecaUun. 

FLEXIBILITY.  The  quality 
in  a  body  which  admits  its  bend- 
ing, or  flexure. 

FLEXURE.  A  winding,  or 
bending.  The  sag  of  a  stick  of 
timber  is  called  its  flexure. 

FLOOR.  The  lower  horizontal 
surface  of  a  room.  Carpenters 
generally  include  in  the  term  the 
timbers  and  joists  on  which  the 
floor-boards  are  laid,  as  well  as 
the  boards  themselves.  There  are 
as  many  respective  floors  to  a 
building  as  the  building  is  stories 
in  height.  The  first  is  usually 
called  the  entrance  story  ;  and  the 
floor  on  which  the  principal  draw- 
ing-rooms are.  the  principal  story. 

FLOOR-JOISTS.  Those  joists 
in  modern  carpentry  supporting 
the  boards  of  the  floor  of  which 
thev  are  a  part. 

FLUSH.  A  term  which  signi- 
fies that  surfaces  are  on  the  same 
plane  or  line.  The  studs  of  a 
wooden  building  are  said  to  be 
flu.tfi  with  the  posts  and  girts. 

FOOT.  A  measure  of  length, 
containing  12  English  in.,  — 
supposed  to  have  taken  its  name 
from  the  length  of  the  human 
foot.  The  term  is  also  used  to  de- 
note surface,  or  solidity;  as  a 
square  fnot,  and  a  solid  or  cubic 
font.  The  length  of  the  lineal 
foot  varies  in  different  countries. 
The  accompanying  table  contains 
its  dimensions,  in  English  in.,  in 
the  principal  cities  of  Europe :  — 


London 12          in. 

Amsterdam  ......  11  2-10 

Antwerp 11  3-10 

Bologna 14  4-10 

Bremen 11  6-10 

Cologne 11  4-10 

Copenhagen 11  6-10 

Dantzic 11  3-10 

Frankfort  on  the  M.    .  11  4-10 

Madrid 12 

Paris 12  1-12 


FORE  or  JACK  PLANE.  The 
plane  used  by  carpenters  to  take 
off  the  rough  surface  of  boards 
and  timbers,  preparatory  to  fi- 
nishing them  with  the  jointer  and 
smoothing-plane. 

FOX-TAIL  WEDGING.  A  me- 
thod of  securing  a  tenon  in  a 
mortise.  It  is  done  by  first  split- 
ting the  end  of  the  tenon,  and 
then  introducing  a  wedge,  a  por- 
tion of  which  is  permitted  to  pro- 
ject from  the  cleft.  The  tenon  is 
then  put  into  the  mortise,  the  back 
or  bottom  of  which,  opposite  the 
end  of  the  tenon,  resisting  the 
head  of  the  wedge,  it  is  forced 
into  the  split  in  the  tenon,  driving 
its  parts  asunder ;  and  it  is  thus 
compressed  and  held  fast  by  the 
cheeks  of  the  mortise. 

FRAME  AND  FRAMING.  The 
rough  timber-work  of  any  build- 
ing, including  roofs,  partitions, 
floors,  &c.  * 

FURRING.  Thin  pieces  of 
wood  nailed  to  beams  or  any  tim- 
bers falling  back  of  the  surface  or 
line  they  are  intended  to  form, 
either  in  consequence  of  sagging, 
or  from  any  original  deficiency  in 
size.  The  term  may  be  appropri- 
ately applied  to  any  pieces  of  wood 
employed  in  bringing  crooked  or 
uneven  work  to  a  regular  surface. 

FUST.  A  term  used  in  some 
parts  of  England  to  denote  the 
apex  or  ridge  of  a  roof. 


G. 

GAUGE.  An  instrument  for 
drawing  lines  on  any  surface  of  a 
piece  of  wood  parallel  to  one  of  the 
arrises  of  that  surface. 


170 


GLOSSARY. 


GABLE  The  vertical  triangu- 
lar piece  of  wall  at  the  end  of  a 
building,  bounded  by  a  horizon- 
tal line  level  with  the  eaves,  toge- 
ther with  the  two  inclined  lines 
of  the  roof. 

GAIN.  The  term  is  probably 
derived  from  the  Welsh  word 
u  £•««,"  a  mortise, and  "'^a/iM,"  to 
contain:  hence  any  piece  of  tim- 
ber, having  one  or  more  mortises, 
may  be  said  to  be  gamed.  Tn 
England,  the  term  more  properly 
applies  to  the  bevelled  shoulders 
of  a  floor-joist,  for  the  purpose  of 
giving  additional  resistance  to  the 
tenon  below  it.  In  America,  the 
term  is  generally  understood  to 
mean  a  notch  or  mortise  cut  into 
the  arris  of  a  beam  or  timber  to 
admit  the  end  of  another.  In 
framing  ordinary  house  and  barn 
floors,  the  joists  are  gained  into 
the  sills  and  girders  instead  of 
being  mortised. 

GAMBREL-1100F.  (See  CURB- 
ROOF.) 

GIMLET.  A  well-known  instru- 
ment used  by  carpenters  and  join- 
ers for  boring  small  holes. 

GIRDER.  The  principal  beams 
or  timbers  in  a  floor  into  which 
the  joists  are  framed.  Their  chief 
use  is  to  lessen  the  bearing  or 
length  of  the  joists. 

GIRT.  The  term ,  when  used  to 
denote  the  size  of  timber,  signifies 
the  circumference,  or  distance 
around  the  outside  of  the  stick, 
and  applies  to  all  timber,  whether 
round  or  square.  Among  Ameri- 
can carpenters,  the  term  is  used  to 
designate  those  horizontal  timbers 
in  the  outside  walls  of  a  wooden 
building  which  are  framed  in  be- 
tween the  posts  at  the  floors  of 
the  several  stories ;  the  timber 
beneath  the  post  being  the  sill, 
and  that  immediately  on  its  top 
the  plate.  Into  the  top  and  bot- 
tom edges  of  the  girt  the  studs 
are  framed;  and  into  its  side,  or 
bridging  it  at  the  top,  the  ends  of 
the  joists  of  the  floor 

GRAIN.  The  direction  of  the 
lines  or  fibres  of  wood.  Thus, 
when  those  lines  are  straight  and 
parallel,  the  wood  is  said  to  be 


straight- grained ;  but,  when  they 
are  twisted  or  crossed,  it  is  said  to 
be  cross- grained, 

GROIN.  The  curved  line  of  in- 
tersection where  two  arches  cross 
each  other. 

GROOVE.     A  sunken  channel. 

GROUND-PLAN.  The  horizon- 
tal section  of  that  part  of  a  build- 
ing lying  next  above  the  surface 
of  the  ground.  A  story,  of  which 
the  floor  is  below  the  surface  of 
the  ground,  is  called  abasement. 


H. 

HALVING.  A  method  of  join- 
ing timbers  by  cutting  away  a 
portion  of  each,  so  that  they  may 
lock  into  each  other. 

H  A  M  M  E  R-B  E  A  M.  A  short 
timber  often  used  in  ancient  tim- 
ber-roofs at  the  foot  of  the  princi- 
pal rafters.  They  extend  a  short 
distance  out  from  the  wall  on  the 
inside  of  the  building,  and  are 
supported  by  a  brace  from  the  un- 
derside. 

HANDSPIKE.  A  lever  of  wood 
for  turning  a  windlass  or  capstan. 

HEADWAY  OF  STAIRS.  The 
clear  distance  or  vertical  height 
from  the  top  of  a  given  stair  to  the 
ceiling  above. 

HEW.  To  cut  with  an  axe  or 
hatchet  so  as  to  make  an  uneven 
and  rough  surface  straight  and 
true.  The  practice  of  hewing 
timber  for  frames  is  nearly  out 
of  use;  most  of  that  used  at  the 
present  day  being  sawed  at  a  mill. 
The  modern  carpenter  is  seldom 
familiar  with  this  process:  still, 
a  competent  knowledge  thereof, 
although  not  often  needed,  is 
essential  to  a  thorough  under- 
standing of  his  profession,  and 
should  by  no  means  be  neglected. 

HI  P-RAFTER.  A  piece  of  tim- 
ber placed  between  the  two  adja- 
cent inclined  sides  of  a  hip-roof 
to  support  the  jack-rafters. 

HIP-ROOF.  A  roof  of  which 
the  end  of  the  sides  is  not  termi- 
nated by  lines  on  the  same  plane 
as  the  ends  of  the  building,  but 
by  hips  formed  by  the  other  sides 


GLOSSARY. 


171 


or  ends  inclining  from  'the  end- 
plates  to  the  ridge. 


I. 

INCH.  A  lineal  measure.  In 
England  and  America,  it  is  the 
sum  of  the  lengths  of  three  barley- 
corns, or  the  twelfth  part  of  a  foot. 

INTER-JOIST.  The  space  or 
interval  between  two  joists. 

INTER-TIES.  Short  pieces  of 
joist  or  timber  used  in  floors  and 
partitions  to  bind  the  work  toge- 
ther. The  word  is  synonymous 
with  bridging. 

IN  THE  CLEAR.  A  phrase 
denoting  the  clear  or  unobstructed 
distance  between  any  two  given 
points.  A  room,  the  ceiling  of 
which  is  ten  feet  above  the  floor, 
is  said  to  be  ten  feet  high  ui  the 
cltar. 


J. 

JACK-PLANE.  A  plane  used 
to  take  off  the  rough  surface  of 
wood  previous  to  its  being  fin- 
ished by  the  jointers  and  smooth- 
ing-plane. 

.)  AC  K-R AFTER.  The  shorter 
rafters,  which,  in  a  hip-roof,  are 
cut  in  against  the  hip-rafters. 

JACK-RIBS.  The  shorter  ribs 
of  a  groin,  which  are  cut  in  against 
the  angle-rib  of  a  groined  ceiling. 

JACK-STCDS.  The  shorter 
studs  in  the  side  of  a  building, 
which  are  cut  in  under  or  upon 
the  braces.  &c. 

JACK-TIMBER.  Any  piece  of 
timber  in  the  frame  of  a  building, 
if  cut  short  of  its  usual  length, 
receives  the  epithet  jack 

JAMB.  The  side  of  any  open- 
ing in  a  wall. 

JAMB-POSTS.  The  posts  at 
the  sides  of  a  door  to  which  the 
jamb-linings  are  affixed. 

JERKIN-HEAD.  A  roof  the 
end  of  which  is  constructed  in 
a  shape  intermediate  between  a 
gable  and  a  hip :  the  gable  being 
continued,  as  usual,  up  to  the  line 
of  the  top  of  the  collar-beam: 


and,  from  this  level,  the  roof  is 
hipped,  or  inclined  backwards. 
This  form  is  rarely  adopted,  except 
in  some  cottages,  or  in  decorative 
architecture. 

JOGGLLJ.  A  joint  so  formed, 
that,  when  its  parts  are  joined,  a 
force  applied  perpendicular  to  that 
which  holds  them  together  will 
not  cause  them  to  slide  past  each 
other.  A  strut  of  a  truss-roof,  or 
a  brace,  when  tenoned  or  let  into 
the  wood  against  it  at  its  end.  in 
any  part  of  a  building,  may  be 
said  to  be  joggled. 

JOINER.  A  mechanic  who  fin- 
ishes a  building  after  it  has  been 
framed,  raised,  and  boarded  by 
the  carpenter.  The  work  per- 
formed by  the  joiner  is  called 
joinery. 

JOINT.  The  place  where  two 
surfaces  meet. 

JOINTER.  The  name  of  the 
two  larger  planes  used  by  joiners. 
They  are  of  two  lengths;  thus 
taking,  respectively,  the  names  of 
lung  and  short  jointer. 

JOISTS.  Those  smaller  timbers 
of  a  building,  framed  into  the 
girders  and  girts,  to  which  the 
floor-boards  are  nailed,  or  into 
the  plates  and  girts  upon  which  is 
nailed  the  outside  boarding.  The 
term,  in  this  country,  generally 
denotes  any  piece  of  timber  more 
than  2  and  less  than  6  in.  square. 
It  is  synonymous  with  the  old 
term  juffers. 


X. 

KERF.  The  channel,  or  slit, 
made  in  wood  by  the  teeth  of  a 
saw.  The  term  is  also  used  to 
denote  the  notches  usually  made 
in  a  stick  of  timber  by  the  hewer, 
before  he  takes  off  the  larger 
pieces  between  the  kerfs. 

KEY.  A  piece  of  wood  ( usually 
of  oak)  let  into  another  to  prevent 
warping.  It  also  denotes  the 
wedge-formed  pieces  sometimes 
put  into  a  mortise  at  the  side  of  a 
tenon  to  prevent  its  being  drawn 
back  out  of  the  mortise.  Also 
those  square  or  round  pieces  usu- 


172 


GLOSSARY. 


ally  put  through  a  scarfing  to 
prevent  its  parts  sliding  past  each 
other. 

KING-POST.  In  old  methods 
of  carpentry,  the  centre-posts  in 
a  trussed  roof.  This  post  is  also 
known  as  curb-post  and  prick- 
post. 


LANDING.  That  part  of  a 
floor  at  the  termination  of  a  flight 
of  stairs,  either  at  the  bottom  or 
top. 

LANTERN.  An  erection  on  the 
top  of  a  roof  or  dome,  having  an 
aperture  for  the  admission  of 
light.  Its  plan  may  be  either 
circular,  elliptical,  square,  or  po- 
lygonal. 

LATH.  Literally,  a  thin  slip 
of  wood.  In  America,  the  word 
is  used  almost  exclusively  to  de- 
note strips  of  Avood  4  ft.  long,  1| 
in.  wide,  and  f  of  an  in.  thick, 
used  for  covering  the  partition- 
studs  and  furring,  preparatory  to 
plastering.  Laths  of  this  kind 
are  cut  from  the  refuse  pieces  of 
timber  called  slabs,  which  are  the 
segmental  pieces  first  cut  from  a 
log  previous  to  sawing  it  into 
boards,  &c.  They  are  put  up  in 
bundles  of  a  hundred  each.  In 
England,  the  term  latli  generally 
denotes  narrow  strips  of  wood 
nailed  to  the  rafters  to  support 
the  slating  or  tiling  of  a  roof;  also 
those  which  support  plastering. 

LEDGMENT.  The  development 
of  a  body  as  stretched  out  or 
drawn  on  a  plane,  so  that  the 
arrangement  of  its  parts,  and  the 
dimensions  of  its  different  sides, 
may  be  readily  seen  and  ascer- 
tained. The  drawing  of  a  roof, 
as  seen  from  a  point  over  it.  is 
said  to  be  a  view  of  the  same  in 
ledg-ment. 

LEDGERS  are,  in  scaffolding, 
the  horizontal  pieces  parallel  to 
the  walls  of  the  building.  They 
are  nailed  to  the  outside  of  the 
poles,  and  opposite  the  end  of 
the  brackets  upon  which  the 
floors  of  the  scaffolding  are  laid. 


LEVEL.  A  horizontal  line,  or 
plane  parallel  with  the  horizon. 
The  term  also  denotes  an  instru- 
ment used  by  artisans  to  decide 
when  lines  or  planes  are  of  equal 
elevation  at  both  ends. 

LINE.  In  geometry,  a  term 
denoting  a  magnitude  of  but  one 
dimension,  which  Euclid  defines 
to  be  length  without  breadth  or 
thickness.  The  term  also  denotes 
the  twelfth  part  of  a  French  in. 
A  right  line  is  the  shortest  straight 
line  that  can  be  drawn  between 
two  given  points  A  horizontal 
line  is  one  level  or  parallel  with 
the  horizon.  A  line  which  is 
plumb  leans  neither  way,  but  is  at 
right  angles  with,  or  perpendicu- 
lar to,  a  level  line. 

LINTEL.  A  horizontal  piece 
of  timber  or  stone,  over  a  door, 
window,  or  other  opening,  to  sup- 
port a  superincumbent  weight. 

LUMBER.  The  term  in  this 
country  is  usually  understood  to 
mean  logs  or  timbers  after  they 
are  cut  and  sawed  or  split  for 
use,  and  applies  to  all  descriptions 
and  dimensions;  such  as  beams, 
boards,  joists,  planks,  shingles, 
&c. 


M. 

M  ROOF.  A  roof  formed  of 
two  common  roofs  by  placing  their 
eaves  against  and  parallel  to  each 
other,  like  the  letter  W  inverted 
(M).  The  design  of  the  M  roof  is 
that  a  larger  space  or  span  may 
be  roofed  over  with  light  timber 
than  could  safely  be  done  were 
the  span  covered  with  a  single 
pitched  roof.  By  the  use  of  the 
M  roof,  a  saving  is  also  made  in 
the  gable-end  ;  the  sum  of  the 
surface  of  the  two  gables  of  the  M 
roof  being  less  than  in  one  large 
gable. 

MALLET.  A  large  wooden 
hammer  used  by  carpenters  for 
driving  the  chisel  in  mortising, 
&c. 

MANSARD  ROOF.  Identical 
with  the  gambrel  or  curb  roof. 
The  Mansard  roof  was  so  named 


GLOSSARY. 


173 


from  its  inventor,  Francis  Man- 
sard, who  was  born  at  Paris  in 
1645.  His  true  name  was  Har- 
douin  Julius  Mansart.  He  was 
an  eminent  architect,  and  was  em- 
•ployed  by  Louis  XIV.  to  build  the 
Palace  of  Versailles  and  the  Hos- 
pital of  the  Invalids.  He  died  in 
1708,  at  the  age  of  sixty-three. 

MENSURATION.  The  science 
which  teaches  the  methods  of 
calculating  the  magnitude  of  bo- 
dies, lines,  and  superfices. 

MODEL.  A  miniature  pattern 
of  the  whole  or  some  part  of  a 
building,  showing  how  the  work 
is  to  be  arranged  and  constructed. 

MORTISE.  A  sinkage,  or  recess, 
in  a  piece  of  timber  to  receive  the 
tenon,  or  end,  of  another  stick. 


N. 

NAKED  FLOORING.  A  term 
denoting  the  timbers  of  a  floor, 
such  as  beams,  girders,  joists,  &c., 
•before  the  boards  are  laid  upon 
them,  or  the  furrings  affixed  be- 
neath. 

o. 

OUT  TO  OUT.  An  expression 
denoting  the  magnitude  of  any 
body  measured  to  the  extreme 
outside. 

OUT  OF  WIND.  An  expression 
used  by  artificers  to  signify  that 
the  surface  of  a  thing  is  a  true 
and  perfect  plane.  A  squared 
piece  of  timber,  which  by  any 
means  has  become  twisted,  is  said 
to  be  winding. 


P. 

PALE.  A  sharp-pointed  stake 
of  wood  used  for  landmarks,  &c. 

PALISADE.  A  fence  or  fortifi- 
cation made  of  stakes,  sharpened, 
and  driven  firmly  into  the  ground. 

PARALLEL.  In  geometry,  a 
tenn  applied  to  lines  or  surfaces 
which  run  in  the  same  direction, 
being  at  every  point  equidistant 
from  each  other. 


PARALLELOGRAM.  Any  four- 
sided  rectilinear  figure  whose  op- 
posite sides  are  parallel.  The  term 
usually  denotes  a  figure  greater  in 
length  than  in  width. 

PARTITION.  A  wall  dividing 
one  room  from  another.  When  a 
partition  is  of  great  length,  and 
is  unsupported  from  beneath,  it 
should  be  trussed :  it  is  then  called 
a  trussed  partition. 

PEDIMENT.  The  triangular 
part  of  a  portico,  or  roof,  which 
is  terminated  by  the  sloping  lines 
of  the  roof.  Pediments  may  be 
either  triangular  or  segmental  in 
contour.  The  term  gable  is  nearly 
identical  with  pediment;  but  the 
latter  term  more  properly  applies 
to  a  gable  when  finished  with 
an  entablature,  taking-mouldings, 
&c. 

PENDENTIVE  CRADLING. 
The  timber-work  which  supports 
the  laths  and  plaster  of  vaulted 
ceilings. 

PERPENDICULAR.  A  line,  or 
surface,  falling  on  another  at  right 
angles.  The  term  also  denotes  a 
line  at  right  angles  with  the  hori- 
zon ;  although,  in  the  latter  case, 
the  proper  term  is  vertical. 

PILES.  Large  unhewn  timbers 
driven  into  the  earth,  upon  the 
heads  of  which  are  laid  the  foun- 
dation-stones of  large  buildings, 
the  piers  of  bridges,  &c.  Piles 
are  used  where  the  soil  is  too  loose 
and  spongy  to  insure  the  founda- 
tion against  settlement  without 
them.  They  are  usually  of  oak 
or  spruce,  and  are  from  7  to  15 
in.  in  diameter.  They  are  sharp- 
ened at  one  end,  and,  if  need  be, 
shod  with  iron,  and  hooped  at  the 
top.  They  are  then  driven  into 
the  ground,  as  far  as  possible,  by  a 
machine,  which  lets  a  heavy  weight 
fall  upon  their  heads  from  a 
height  of  about  30  ft.  Piles,  when 
driven  so  far  below  the  surface  of 
the  ground  that  water  always  re- 
mains over  them,  are  quite  im- 
pervious to  decay.  Nearly  the 
entire  city  of  Amsterdam  is  built 
on  piles.  The  foundation-stones 
of  the  new  Custom  House  in  Bos- 
ton rest  on  more  than  three  thou- 


174 


GLOSSARY. 


sand.  They  are  driven  at  dis- 
tances of  2  ft.  from  centres. 

PIN.  A  piece  of  wood,  com- 
monly of  chestnut  or  oak,  sharp- 
ened at  one  end,  and  used  to 
confine  timbers  together.  Pins 
made  by  hand,  and  therefore  left 
somewhat  rough,  are  preferable 
to  those  made  by  a  machine,  as 
the  latter,  being  nearly  smooth 
and  round,  easily  turn  or  work, 
when  the  wood  about  them  has 
shrunk  in  drying;  whereas  those 
made  by  hand  are  polygonal,  and, 
when  driven  into  holes,  their 
angles  cut  into  the  wood,  and 
they  are  thereby  effectually  pre- 
vented from  turning.  Small  pins 
are  called  pegs.  The  pins  used 
in  ship-building  are  made  by  ma- 
chinery, and  are  called  treenails. 

PITCH.  In  carpentry,  the 
term  denotes  the  angle  formed  by 
the  inclined  sides  of  a  roof.  In  a 
building  where  the  extreme  height 
from  the  top  of  the  rafters  at  the 
ridge  is  one-third  of  the  width  of 
the  building  at  the  eaves,  from 
u  out  to  out,"  the  roof  is  said  to 
be  one-third  pitch  ;  if  one-quarter 
the  width,  nnr-quartcr  pilch.  If 
it  be  10  ft.  from  the  top  of  the 
rafters  to  a  line  level  with  the 
eaves,  it  is  10-ft.  pitch. 

PLAN.  The  representation  of 
the  horizontal  section  of  a  build- 
ing, showing  the  disposition  of 
the  rooms  by  the  arrangement 
of  the  partitions,  &c.  The  word 
plan  is  quite  extensive  in  its  sig- 
nification, and,  as  commonly  used, 
denotes  the  general  idea;  hence, 
the  design  of  the  several  parts  of 
a  building,  whether  as  regards 
finish,  arrangement  of  rooms,  or 
the  composition  as  a  whole,  may 
with  propriety  be  termed  its  plan ; 
but,  among  architects,  the  term 
more  properly  denotes  a  drawing 
exhibiting  the  form,  arrangement, 
and  size  of  the  rooms  on  the  se- 
veral floors.  A  representation  of 
a  front  or  side  is  called  an  eleva- 
tion. 

PLANK.  A  piece  of  timber  of 
any  length,  having  a  width  of 
more  than  6  in.,  and  from  2  to  6 
in.  thick.  If  less  in  thickness 


than  2  in.,  it  is  usually  called  a 
bnard.  If  the  piece  be  less  in 
width  than  6  in.,  and  not  thin 
enough  to  be  called  a  board,  it  is 


ed  a  j»i 
.,  it   is 


commonly   called   a* 


termed  a  joist.     If  thicker   than 

6  in 

timbf 

PLATE.  The  horizontal  piece 
of  timber  that  lies  immediately 
on  the  top  of  the  posts  of  a  frame, 
or  on  the  top  of  the  walls  of  a 
brick  or  stone  building.  Oatter- 
platKs  are  pieces  of  timber  framed 
out  from  the  side-walls  for  the 
support  of  the  gutter. 

PLATFORM.  An  assemblage 
of  timbers  laid  in  a  horizontal 
position,  and  covered  with  planks 
or  boards,  like  a  floor. 

PLUMB.  A  line  perpendicular 
to,  or  at  right  angles  with,  the 
horizon.  A  level  line  and  a  plumb- 
line  form  a  right  angle  when  they 
are  brought  in  contact.  Hence, 
if  one  of  the  blades  of  a  carpen- 
ter's framing-square  be  placed  on 
the  edge,  in  a  level  position,  the 
other  blade,  being  at  right  angles 
with  it,  will  be  a  plumb-line. 

PLUMB-RULE.  An  instrument 
for  determining  plumb-lines. 

POST.  Any  piece  of  timber 
used  in  a  vertical  position  to  sup- 
port a  superincumbent  weight,  or 
to  support  the  horizontal  timbers 
in  the  frame  of  a  building 

PROTRACTOR.  Aninstru- 
ment  for  laying  down  angles. 
They  are  usually  made  of  brass 
or  German  silver. 

PUNCHEON.  Nearly  synony- 
mous with  post.  It  also  denotes 
the  short  studs  in  a  partition  over 
a  door.  The  word  puncheon  pro- 
perly designates  an  upright  post 
or  arbor  in  any  machine  which 
turns  vertically;  as  a  crane,  for 
instance. 

PURLINS.  The  horizontal 
pieces  of  timber  which  lie  on  the 
trusses  of  a  roof,  and  support 
the  common  rafters. 


Q. 

QUEEN-POST.     A  suspension- 
post  in  a  trussed  roof  where  two 


GLOSSARY. 


175 


posts  are  employed  in  the  truss 
instead  of  one,  as  is  the  case  with 
a  truss  framed  with  a  king-post. 


E. 

RABBET.  A  recess,  or  channel, 
cut  into  the  arris  of  a  piece  of 
wood.  A  channel  cut  into  a  plane 
surface  is  called  a  groove. 

RADIUS.  The  semidiameter  of 
a  circle,  or  the  length  of  a  right 
line  drawn  from  the  centre  to  the 
circumference. 

RAFTEKS.  The  inclined  tim- 
bers of  a  roof,  which  support  the 
covering.  Those  forming  part  of 
a  truss,  and  which  support  the 
purlins,  are  called  truss-rafters. 
The  smaller  rafters  to  which  the 
boards  are  nailed  are  called  com- 
mon rafters. 

RAIL.  A  term  in  architecture 
of  many  meanings,  but  .denoting 
more  particularly  any  timbers  or 
pieces  of  wood,  in  the  rougher 
kinds  of  work,  lying  in  a  horizon- 
tal position,  as  in  fences,  &c. 

RELISH.  A  term  denoting  the 
piece  cut  out  between  two  tenons 
existing  on  the  same  piece  of 
wood;  also  a  piece  cut  from  the 
edge  of  a  tenon  when  it  would  be 
too  wide  if  its  whole  width  were 
left. 

RESISTANCE.  The  power  or 
quality  in  a  body  which  enables 
it  to  avoid  yielding  to  force  or  ex- 
ternal pressure  of  any  kind,  and 
which  lessens  the  effect  of  the  op- 
posing power;  as  the  resistance 
of  water  to  the  motion  of  a  ship, 
or  that  of  wood  to  the  operation 
of  a  cutting  instrument.  The  fol- 
lowing table  exhibits  the  degree 
of  resistance  to  pressure  in  the 
more  common  kinds  of  woods, 
taking  common  New-Jersey  free- 
stone as  the  unite  — 

Freestone 1 

Alder,  Birch,  or  Willow    ...  6 

Beech,  Cherry,  Hazel 6| 

Holly,  Elder,  Pear,  and  Apple  7 

Walnut,  Thorn 74 

Elm,  Ash 8* 

Box,  Plum,  Oak 11 


The  resistance  of  lead  by  the  same 
unit  is  6^;  brass,  50;  iron,  107. 

RIB.  A  curved  piece  of  wood 
I  used  for  supporting  the  lathing 
I  and  plastering  of  a  vaulted  ceil- 
I  ing,  or  the  boarding  of  a  dome. 

RIDGE.  The  highest  line  of  a 
roof  at  the  angle  made  by  the 
meeting  of  the  top  of  the  rafters. 
The  piece  of  wood  against  which 
the  top  ends  of  the  rafters  bear  is 
called  the  ridge-piece,  or  ridge- 

P<RIGHT  LINE.  The  shortest 
line  that  can  be  drawn  between 
two  given  points. 

ROD.  The  term  literally  signi- 
fies any  thing  which  is  long  and 
slender,  and  may  be  used  to  de- 
note either  a  piece  of  wood  or  me- 
tal. It  denotes  also  a  measure  of 
i  length,  being  16i  ft. 

ROLLS  or  ROLLERS.  Plain 
;  cylinders  of  wood  used  in  moving 
!  large  timbers  or  other  heavy  ma- 
!  terials.  They  are  usually  from  3 
!  to  10  in.  in  diameter,  and  from 
!  1  to  6  ft.  long.  To  move  one  end 
;  is  called  cutting  the  roller. 

ROOF.  The  exterior  horizontal 
covering  of  a  building. 

ROOFING.  The  general  assem- 
blage of  timber  and  other  mate- 
rials which  compose  'the  roof  of  a 
building. 

ROTUNDA.    A  building  round 

on  its  exterior  and  interior,  as  the 

Pantheon  at  Rome.    The  term  is 

often   used,  however,   to    denote 

any  large  circular  room  the  ceil- 

i  ing   of   which   is   arched   like   a 

\  dome.    The  large  room  beneath 

the  great  centre  dome  of  the  Ca- 

i  pitol,  at  Washington,  is  commonly 

called  the  RutunUa. 


SAG  or  SAGGING.    The  bend- 
ing or  yielding  of  a  stick  of  tim- 
;  her  between  the  points  of  support 
when  the  timber  lies  either  in  a 
horizontal  or  an  inclined  position. 
SALLY.     A   projection  of  any 
kind.    In  carpentry,  the  term  de- 
!  notes  the  end  of  a  piece  of  timber 
!  when  cut  to  an  acute  angle,  ob- 


176 


GLOSSARY. 


liquely  to  the  fibres  of  the  wood. 
For  example,  the  lower  end,  or 
foot,  of  common  rafters,  where 
they  are  connected  with  the  plate ; 
the  end  of  a  stair-carriage,  &c. 
The  outer  point  is  called  the  toe ; 
and  the  inner  point,  the  heel. 

SAW-PIT.  The  pit,  or  excava- 
tion, over  which  timber  is  sawed. 
Formerly  the  labor  was  done  by 
two  persons,  one  standing  in  the 
pit,  and  the  other  on  the  top  of 
the  log.  The  men  who  performed 
the  work  were  called  sawyers. 
This  work  is  now  done  by  ma- 
chinery ;  and,  fortunately  for  the 
carpenter,  he  is  now  seldom  called 
upon  to  render  so  laborious  a  ser- 
vice as  that  of  sawing  logs  by  the 
severe  and  slow  process  of  hand- 
labor. 

SCAFFOLDING.  An  assem- 
blage or  structure  of  joists  and 
boards,  or  planks,  used  in  erect- 
ing or  decorating  the  walls  of  a 
building.  Scaffoldings  are  usually 
built  by  first  erecting  joists  in  a 
perpendicular  position,  at  suita- 
ble distances  apart,  and  nailing 
boards  to  the  outside  of  them  at 
distances  of  every  6  ft.  in  height, 
in  a  horizontal  position,  and  pa- 
rallel to  the  walls  of  the  building. 
The  joists  are  called  stage-poles; 
and  the  horizontal  boards,  ledgers. 
At  every  pole,  and  at  right  angles 
•with  the  ledgers,  are  other  boards, 
continued  in  from  them  to  the 
walls.  The  last-named  pieces  are 
called  brackets.  These  are  covered 
with  a  floor  of  boards,  simply  laid 
on  the  brackets  without  nailing. 
The  word  stagin g is  often,  though 
improperly,  used  among  workmen 
for  scaffolding.  A  kind  of  scaf- 
folding is  sometimes  used  in  the 
erection  of  wooden  buildings, 
which  consists  of  what  are  termed 
wooden  jacks ;  they  being  confined 
to  the  walls  by  means  of  a  bolt, 
with  a  nut  on  the  inside.  The 
jacks  support  boards,  forming  a 
floor  as  in  a  scaffolding,  with 
brackets  and  poles. 

SCALE.  An  implement  for 
measurement.  Scales  are  usually 
made  on  wood  or  metal,  and  are 
of  three  kinds;  viz.,  the  plain 


scale,  the  Gunter^s  scale,  and  the 
diagonal  scale.  The  plain  scale 
contains  simple  divisions  of  any 
required  dimension.  The  Gunter's 
scale  is  marked  by  various  lines 
and  numbers,  by  which,  with  the 
aid  of  a  pair  of  dividers,  many 
questions  in  arithmetic  and  prac- 
tical geometry  are  readily  solved: 
it  is  usually  2  ft.  long  and  2  in. 
wide.  The  diagonal  scale  is  formed 
by  dividing  its  width  into  a  cer- 
tain number  of  parts,  and  then 
drawing  diagonal  lines  across 
them.  By  this  implement,  mea- 
surements may  be  made  with 
great  exactness.  The  word  scale 
also  refers  to  the  magnitude  of  a 
drawing,  map,  or  other  object,  as 
compared  with  its  original. 

SCANTLINGS.  A  term  some- 
times used  to  denote  small  tim- 
bers; as  joists,  &c. 

SCARFING.  The  joining,  or 
splicing,  two  pieces  of  wood,  so 
that  the  whole  may  appear  as  but 
one  piece. 

SCRIBING.  Fitting  the  edge 
of  a  piece  of  wood  to  the  surface 
of  another. 

SECTION.  A  geometrical  rep- 
resentation of  a  part  of  the  inte- 
rior of  a  building  as  cut  by  a 
vertical  or  horizontal  plane.  A 
section  not  only  exhibits  the  lines 
where  the  separation  is  made,  but 
also  the  elevation  of  those  parts 
of  the  building  exposed  to  view, 
if  the  nearer  sectional  part  was 
actually  removed.  A  longitudinal 
section  is  one  on  a  line  with  the 
length  of  the  building;  a  trans- 
verse section  is  one  on  a  line  with 
its  width,  or  across  it;  and  a  ho- 
rizontal section  shows  the  floors, 
being  usually  called  the  plan. 
The  term  section  also  denotes  a 
part,  or  portion,  considered  as 
separate  from  the  rest. 

SEGMENT.  A  part  or  piece 
cut  from  any  thing,  particularly 
the  portion  contained  between  the 
chord  and  arc  of  a  circle. 

SEVERY.  A  compartment  or 
division  of  scaffolding. 

SHAKE.  A  crack,  or  fissure, 
in  wood,  caused  by  its  being  dried 
too  rapidly.  A  piece  having  many 


GLOSSARY. 


177 


slits,  or  clefts,  is  said  to  be 
shaky. 

SHORE.  A  prop,  or  brace, 
standing  in  an  oblique  position 
against  a  wall  to  retain  it  in  its 
proper  place.  To  "  shore  up  a 
wall  "  is  to  put  shores  against  it. 

SHOULDER.  The  plane  at  the 
tenoned  end  of  a  stick  of  timber, 
which  is  transverse  to  its  length, 
and  at  right  angles  with  the  tenon 
projecting  from  it. 

SILL.  The  lowest  principal 
piece  of  timber  in  the  frame  of 
a  structure  which  lies  in  a  hori- 
zontal position. 

SITE.  The  situation  or  lot  of 
land  on  which  a  structure  stands. 

SLEEPERS.  Pieces  of  timber 
which  lie  horizontally  on  the 
ground,  under  the  principal  tim- 
bers of  a  ground-floor. 

SLIDING-RULE.  One  haying  a 
figured  slide,  which,  being  moved 
against  logarithmic  lines,  deter- 
mines various  arithmetical  calcu- 
lations. 

SOCKET-CHISEL.  Same  as 
firmer-chisel. 

SPAN.  The  distance,  or  spread, 
between  the  eaves  of  a  roof,  the 
abutments  or  piers  of  a  bridge, 
&c. 

SPAN-ROOF.  A  roof  consist- 
ing of  two  simple  inclined  sides 
in  contradistinction  to  shed-roof. 

SPIRE.  That  part  of  a  steeple 
which  diminishes  as  it  ascends. 
Any  tapering  body. 

S'PLAYED.  A  term  denoting  a 
side  which  makes  an  oblique  angle 
with  that  adjoining.  The  jambs 
of  a  window  are  often  splayed; 
thus,  by  making  the  aperture 
larger  in  the  room,  admitting 
more  light. 

SQUARE.  A  figure  of  four 
equal  sides,  and  as  many  right 
angles.  Also  an  instrument  used 
by  carpenters  and  joiners  for  lay- 
ing out  and  squaring  their  work. 
(?ee  CARPENTER'S  SQUARE.)  A 
thing  is  said  to  be  square  when 
its  angles  are  right  angles. 

STAGE.  A  floor  on  which 
actors  perform  in  a  play-room. 
In  ancient  theatres,  the  stage  was 
culled  the  proscenium.  This  term 


in  modern  times  denotes  more 
particularly  the  front  of  the  stage 
at  the  line  where  the  curtain  fells. 

STANCHION.  A  prop,  or  sup- 
port. The  term  is  nearly  synony- 
mous with  post. 

STARLINGS.  An  English  term 
denoting  piles  driven  about  the 
piers  of  a  bridge,  or  the  sides  of  a 
timber- wharf,  to  give  them  sup- 
port. 

STAY.  Any  thing  performing 
the  office  of  either  a  tie  or  a  brace, 
which  prevents  the  swaying  of 
the  work  to  which  it  is  affixed. 

STEEPLE.  The  lofty  erection, 
!  ending  in  a  point,  which  sur- 
|  mounts  a  church.  It  is  composed 
of  a  tower  and  spire.  The  tower 
extends  from  the  ground  to  the 
line  where  the  steeple  begins  to 
diminish.  From  this  point,  the 
remainder  is  called  the  spire. 
Where  the  edifice  has  a  porch  or 
projection  in  front,  the  steeple  is 
considered  to  begin  at  the  top  of 
the  porch  named. 

STORY.  That  vertical  division 
of  a  building  occupying  the  space 
from  the  top  of  one  floor  to  the 
under  side  of  that  immediately 
over  it.  A  building  is  said  to  be 
as  many  stories  high  as  there  are 
alternate  spaces  of  this  description 
from  the  top  of  the  sills  to  the 
top  of  the  plates  at  the  eaves. 
In  America,  the  principal  story  is 
usually  on  the  first  floor :  in  Eng- 
land, it  is  on  the  second.  In  this 
country,  we  usually  denominate 
the  first  story  above  the  ground 
the  principal  or  entrance  story ; 
that  above  this,  the  chamber-story ; 
and  those  above  them,  the  third, 
fourth,  fifth  stories,  &c. 

STORY-POST.  A  post  between 
two  adjoining  stories  of  a  building, 
for  supporting  a  superincumbent 
weight. 

STRAIN.  The  force  exerted  on 
any  material  which  tends  to  de- 
stroy the  cohesion  of  its  parts. 

STRAINING-PIECE.  A  piece 
placed  between  two  opposite  pieces 
of  timber  to  prevent  their  nearer 
approach.  It  is  always  in  a  state 
of  compression. 

STRAP.    An  iron  plate,  bar,  or 


12 


178 


GLOSSARY. 


band  for  confining  together  two 
or  more  pieces  of  timber. 

STRIATED.  Marked  with 
small  furrows,  or  channels,  as 
those  in  a  piece  of  wood  sawed  by 
a  large  saw  in  the  direction  of  its 
length.  When,  in  sawing  lumber, 
the  saw  is  not  firmly  fixed  in  the 
frame,  the  sides  of  the  timber  are 
made  rough  or  ridgy,  and  are  then 
said  to  be  striated. 

STRIKING.  This  term  denotes 
the  act  of  lining  out,  or  marking 
off  the  surface  of  any  piece  of 
timber,  for  making  mortises,  te- 
nous,  &c. ;  also  removing  the  cen- 
tering on  which  a  vault  or  arch 
has  been  built. 

STRUT.  This  term  is  nearly 
synonymous  with  brace;  and,  if 
it  may  be  more  properly  used  in 
any  case,  it  is  when  it  denotes  a 
timber  designed  to  keep  extended 
those  parts  of  the  work  against 
which  its  ends  come.  The  term 
brace  may  be  used  as  a  substitute 
for  strut,  but  not  strut  for  brace. 
A  strut,  therefore,  is  always  in  a 
state  of  compression,  while  a  brace 
may  be  either  compressed  or  ex- 
tended. 

STUBSHOD.  A  term  in  com- 
mon use  among  carpenters  and 
joiners  to  denote  the  roughly  split 
wood  at  the  end  of  a  piece  of  tim- 
ber, not  sawn  through,  but  split 
or  cleft  apart,  after  the  log  was 
removed  from  the  track  over  the 
saw-pit. 

STUDS.  Those  short  timbers, 
or  joists,  framed  into  the  sides 
and  ends  of  wooden  buildings  to 
complete  the  framing  of  the  wall. 
Those  at  the  sides  of  windows  are 
generally  made  somewhat  larger 
than  the  rest,  and  are  called  win- 
dow-studs :  those  cut  in,  under,  or 
over  the  braces  are  called  jack- 
studs.  Of  late  years,  the  term  is 
used  to  denote  also  those  timbers, 
or  joists,  called  partition-studs,  to 
which  the  lathes  are  nailed  in  par- 
titions. In  England,  partition- 
studs  are  usually  called  quarters. 

STUFF.  This  word  is  used  by 
carpenters  and  joiners  to  denote 
indiscriminately  lumber  of  any 
kind.  Lumber,  sawed  to  any  par- 


ticular size  or  dimension,  is  called 
dimension-stuff.  It  is  to  the  car- 
penter and  joiner  what  the  gene- 
ral term  stuck  is  to  other  me- 
chanics. 

SUMMER.  Any  large  beam 
designed  to  cover  a  wide  opening. 
A  small  summer  is  called  a  lintel. 

SUPER.VI'RUCTURE.  That  part 
of  an  edifice  erected  above  the 


T. 

TAIL-TRIMMER.  A  piece  of 
timber,  into  which  the  ends  of 
joists  are  framed,  where  chimney- 
flues,  or  any  thing  of  like  nature, 
prevent  the  insertion  of  the  ends 
of  the  joists  as  may  be  done  where 
the  wall  is  solid. 

TAPERING.  A  term  denoting 
that  the  sides  of  a  body  gradually 
approach  each  other  in  the  di- 
rection of  their  length;  so  that, 
if  continued,  they  would  meet  at 
a  point. 

TEMPLET.  A  short  piece  of 
timber  laid  under  the  end  of  a 
beam  or  girder  in  the  walls  of 
a  brick  or  stone  building. 

TENON.  The  end  of  any  piece 
of  wood  so  reduced  as  to  fill  and 
fit  into  a  mortise.  The  tenon  pro- 
jects from  the  rest  of  the  wood; 
and  the  place  where  it  commences 
is  so  cut  as  to  form  a  surface  at 
right  angles  with  it  called  the 
shoulder. 

TENSION.  The  stretching  or 
degree  of  extension  to  which  a 
thing  may  be  strained  in  the  di- 
rection of  its  length. 

THRUST.  The  force  exerted 
by  one  body  against  another;  as 
that  of  a  segmental  arch  against 
its  abutments,  or  the  rafters  of  a 
common  roof  against  the  plates. 

TIE.  A  timber,  chain,  or  rope 
so  fixed  as  to  retain  two  bodies  in 
a  particular  position  when  a  ten- 
dency exists  to  diverge  or  spread 
apart. 

TIE-BEAM.  The  beam  at  the 
foot  of  a  pair  of  large  rafters, 
serving  to  tie  the  walls  of  the 
building  together  by  counteract- 


GLOSSARY. 


179 


ing  the  thrust  exerted  by  the 
rafters  named. 

TIMBER.  This  term  is  used  so 
indefinitely,  that  it  is  a  matter  of 
some  nicety  to  lay  down  any  defi- 
nition which  will  not  clash  with  so- 
called  "  well-established  usage." 
The  true  meaning  of  the  word 
seems  to  be  wood  fit  for  buildings. 
And,  as  used  at  present,  it  denotes, 
1st,  The  trunks  and  larger  limbs 
of  trees  either  standing  or  cut 
down  ;  2d,  All  large  sticks,  after 
they  are  sawed  or  hewn  out,  and 
squared  for  use. 

TOE  OF  A  RAFTER.  The  ex- 
treme point  of  a  rafter,  after  it  is 
so  cut  at  the  end  that  it  may  fit 
on  the  plate.  The  inner  point  is 
called  the  keel  of  the  rafter. 

TOEING.  An  expression  de- 
noting a  nail,  or  other  article, 
driven  diagonally  through  one 
piece  of  wood  to  confine  it  to 
another.  Nails  are  driven  toeing 
into  wood,  when,  from  the  pecu- 
liar form  of  the  piece  and  the  dis- 
position of  the  parts  to  be  con- 
fined together,  it  is  difficult  to  use 
the  nail  at  right  angles. 

TORSION.  The  strain  on  any 
material  which  tends  to  cause  the 
same  to  twist  or  wind. 

TRANSVERSE.  A  cross  direc- 
tion. The  transverse  strain  on  a 
piece  of  timber  is  when  the  force 
is  so  applied  as  to  break  it  down 
when  it  lies  in  a  horizontal  posi- 
tion. 

TRAMMEL.  An  instrument 
for  describing  an  ellipse,  or  oval. 

TRIM.  To  fit  or  prepare  any 
piece  of  wood  so  as  to  make  it 
suit  another.  To  make  a  tenon 
smaller,  that  it  may  fit  into  a 
mortise,  is  to  trim  it  up. 

TRIMMER.  A  small  beam  into 
which  is  framed  the  ends  of  floor- 
joists  at  an  opening  in  a  floor. 
The  joists  into  which  the  ends  of 
trimmers  are  framed  are  called 
trimming-joists.  Trimmers  are 
used  at  the  sides  of  well-rooms,  of 
stairs,  against  chimneys,  &c.  The 
last  are  usually  called  tail-trim- 
mers. 

TRUNCATED.  A  term  denot- 
ing that  the  top  or  apex  of  any 


thing  Is  cut  off.  The  part  that 
remains  is  called  the  frustum.  A 
hip-roof,  the  rafters  of  which  do 
not  continue  up  to  a  point,  but 
end  against  a  framed  platform,  is 
said  to  be  truncated. 

TRUSS.    A  peculiar   combina- 
tion and  arrangement  of  timbers 
hi    framing,    whereby    they    are 
made  to  mutually  support  each 
I  other. 

TRUSSED   PARTITION.     A 
partition  having  a  truss  within  it. 
i  Partitions  are  trussed  when,  from 
j  the   arrangement   of   the    rooms 
I  under   it,  a   support   cannot   be 
!  given  from  below  without  inter- 
fering with  the  clear  space  of  the 
i  room. 

TRUSSED    BEAM.      One    con- 
i  taining  the  principles  of  a  truss. 

TRY.    To  plane  out  a  piece  of 

;  wood  true  and  square.    The  act 

of  squaring  wood  by  the  plane, 

preparatory  to  putting  the  work 

together,  is  called  trying  it  out. 

TUSK.  A  bevelled  shoulder 
made  on  the  end  of  a  piece  of 
framing-timber  above  the  tenon. 
j  The  tusk  is  framed  into  the  beam 
or  girder,  and  is  designed  to  give 
additional  strength  to  the  tenon. 


TJ. 

UPHERS.    An  old  term  denot- 
ing small  poles  or  sticks  of  tim- 
[  her  partially  squared.    They  were 
used  for  scaffolding,  common  roofis, 
&c. 

V. 

VALLEY.    The  line  at  the  in- 
ternal meeting  of  the  two  inclined 
sides  of  a  roof.    The  rafter  under 
i  the  valley  is   called   the   vaUey- 
I  rafter. 

VAULT.     An   arched   roof  or 
!  ceiling  over  an  apartment. 

VAULTED.    Arched  like  a  vault 
I  or  the  interior  of  a  dome. 

VERTEX.  The  point  of  termi- 
nation of  any  thing,  the  sides  of 
which  are  inclined  and  continued 
till  they  meet;  as  a  cone  or  a 
common  roof. 


180 


GLOSSARY. 


w. 

WALL.  The  sides  or  ends  of 
any  building  or  apartment. 

WALL-PLATE.  A  piece  of 
timber  placed  horizontally  on  the 
top  of  a  wall.  The  term  plate  de- 
notes the  same  thing. 

WEDGE.  One  of  the  five  me- 
chanical powers.  It  has  five  sur- 
feces;  is  thick  at  one  end,  and 
slopes  to  a  thin  edge  at  the  other. 

WELL-HOLE.  The  open  hole, 
in  a  flight  of  stairs,  at  the  end  of 
the  steps. 

WICKET.  A  small  door  made 
through  a  larger  door  or  gate. 


WINDLASS.  A  machine  for 
raising  weights.  It  consists  of  a 
strong  cylinder  of  wood  or  iron, 
which  moves  on  an  axis,  and  is 
turned  by  a  crank,  or  by  means 
of  levers  inserted  in  mortises  cut 
into  the  outside  of  the  cylinder 
near  the  ends.  Around  the  cy- 
linder is  wound,  by  its  revolu- 
tions, a  rope  or  chain,  the  other 
end  of  which  is  attached  to  the 
weight  to  be  raised.  The  wind- 
lass is  used  in  a  horizontal  posi- 
tion. The  capstan,  an  instrument 
of  the  same  nature,  is  used  up- 
right. (See  CAPSTAN.) 


THE    END. 


FOURTEEN  DAY  USE 

RETURN  TO  DESK  FROM  WHICH  BORROWED 


This  book  is  due  on  the  last  date  stamped  below,  or 
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